TOPIC: 65 merc 1000 update

Sometimes its the simplest of things.... is the tank vent open? No air in means no gas out (I've don't that more than a few times). A vacuum builds up in the tank that eventually the fuel pumps cant overcome.

If not that.....
I had a similar issue with crappy or no idle but she would run at
1/4 or more throttle, which as time went on got worse and worse. Turned out to be a split fuel pump diagram. If the 65s is much like the 63's (I suspect so) they are easy to check. Just take the pump covers of and, paying attention to how they come out so you can put them back in correctly, take them out and check them.

thanks peter, i dont think that a closed vent is a possibility, the vent appears to be a hose deal that goes out the boat opposite the bilge pump. i havent noticed any sort of vent lever or anything to close it. I will check the pump diaphragms though. I really appreciate your help, I wondered if anyone would bother to read the entire "novel" of a thread !!

Double check your vents. I had on that was clogged afew yrs back with scummy water. Took me about a week to figure it out after I went through everything else on the fuel system. Skip.

So today I removed the vent tube for the fuel tank , she was all d what i thought was clear as was the vent on the starboard side. I also unscrewed and removed what I thought to be the fuel sender in the tank, however it was just the float for the gauge. it looked fine. I also removed both fuel pumps and checked the diaphragms which also looked fine. I pumped up the primer bulb til firm and didnt notice any leaks. Any other ideas ? should I just give it another shot ? maybe adjust the carbs even further from closed to the right ? i found a merc mechanic about an hour away near a large reservoir. he charges $95 an hour !! should i take it to him perhaps even just to diagnose ? any thoughts ?

any ideas ??? should I start a new thread ?

Has the magneto / distributor been checked out properly.

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Have you used a timing light to see if it is a spark issue ? ----Will spark jump a gap of 5/16" on all 6 cylinders ?

One more thought on fuel delivery. Check the filters in the carbs. Are they clear? Maybe there was junk in the can and that long run clogged them up.

Failing that, I'd agree with the professor in that the next thing to look over is ignition. Start with the simple things. Are all the plug wires snug on the plugs. Are all the plugs sparking (see the caution below). Are the ignition wires tight on the terminal blocks. Next, assuming the 65 has breaker points, take off the distributor cap and look for cracks or black lines on the cap. A cracked or arcing cap will cause issues and get worse with use. Now it's time to check the points and timing. Before anyone goes into that, have the points and timing recently been gone over recently?

A caution on checking spark on plugs, or anytime you are cranking the engine during diagnostics. Make sure the fuel line is disconnected, and remember that there is gas in the carbs. I was cranking it in the garage one evening (with no intention of letting it run), but forgot about the gas in the carbs. By cranking the engine I was pumping gas out onto the floor. She backfired and KABOOM!! 5 feet of flames. Fortunately, I maintain a working have a fire extinguisher in my shop at all times and within seconds the fire was out. But what a hell of a mess to clean up (not to mention the near heart attack)

I have been wondering if any one else would suspect a bad fuel oil/mix. I have been trying to think of why it would rip one day then two days later barely stay running. The only variable between these two days was that I added gas after nearly running out on the first occasion. Could I have merked the mix ? I bought the expensive high octane (91) stuff, so I am reluctant to dump it out. What would happen if I added more gas in like 1/2 gallon increments ? Or should I use my back up tank with fresh fuel ? I have not used this smaller tank yet, it was previously used for the trolling motor,which I replaced with an electric. Thoughts... any of you gentleman ?

I have been wondering if any one else would suspect a bad fuel oil/mix. I have been trying to think of why it would rip one day then two days later barely stay running. The only variable between these two days was that I added gas after nearly running out on the first occasion. Could I have merked the mix ? I bought the expensive high octane (91) stuff, so I am reluctant to dump it out. What would happen if I added more gas in like 1/2 gallon increments ? Or should I use my back up tank with fresh fuel ? I have not used this smaller tank yet, it was previously used for the trolling motor,which I replaced with an electric. Thoughts... any of you gentleman ?

You must not guess with oil mix !!

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The motor needs the oil for lubrication of precision parts ( expensive stuff ) it does not need the oil to run.

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What that means is , if you are unsure of what mix is in the tank then put it in your car and mix a new tank with 50:1 using a good oil !

Agreed on the fuel/oil mix - if you are not sure - use that gas elsewhare, not in the Merc. It's imperative.

Here is a random thought. Is it pumpining water? If not, or not well, and it gets really hot, it will run really bad ior not at all (not to mention will cook the motor). If you are not sure - need to check the impeller.

Didnt see an answer to the ignition question - have the points and ignition timing/synco been done lately?

Peter, she is pumping water, since I replaced the impeller about a month ago. The ignition has not been checked, but doesnt seem probable to me since she started up and ran real well on my previous outing. Regardless I will still try to check it this weekend. Gotta wait til payday to buy a timing light. Thanks for the input sir. Im not sure I want to put gas that was mixed with 2 stoke oil in my car tho... just wondered if not having my mix right could be the culprit. The boat came with a partially used 1 gallon sized (yellow) jug of oil, which I have been using til the last outing. When it ran out, I bought some of the stuff wal mart sells. I dont think this would cause to many problems tho ...

Most cars do not mind a bit of oil in the fuel !-It will do no harm.-If you are not sure about the ignition it needs to be checked.--As rubbing block wears the point gaps gets smaller and that does affect timing / spark intensity.

There is also a possibility that you have experienced ethanol phase separation. It is easy to check, remove the high speed jet cover and see what runs out. Capture it in a container if you can. Does it look like mixed gas (blue or green) or is it clear/cloudy white? If it is not fuel you will need to clean out your system completely and refill with fresh fuel and oil. Just went through this with my inline6. I added 6 gallons of fresh fuel that had ethanol in it and the ethanol and water separated from the gas.

So After dumping the 5 gallons of gas from the boat into my truck I refilled with fresh stuff again.I used 15oz of oil to 5 gallons gas. got out to the lake to find the water level so low they had to remove to dock ! Since it was pretty windy I decided to let her warm up still attached to the winch. I gave it a few minutes with the lever up, then a few more with it down at idle. She ran great !! top end roared with man balls!! It just needed this long warm up every time I restarted. At low speed she seemed like she wanted to putt out a lil but never did. Is that the right ratio for 50:1 ? they say to use 8 oz oil to 2.5 gallons gas, but they say to use 16oz oil to 6 gallons ?? this math does not quite add up.

Did you ever change the fuel pump diaphragm or install a kit? I'm thinking there may be a pin hole or slight crack or some detereration thats not noticable that won't show up with your tests? After reading this whole thread I thought you running off a seperate fuel source would resolve the issue? I wouldn't mess with any electronics till all the fuel supply system is checked out or replaced imo. As it did run well doing any adjusting to timing or points might cause you more issues unless your sure ya know how...Sure would like to know whats causing the problem, not a good thing to walk your boat to the dock ...

thanks for checking in on me Bill. I did remove both diaphragms and check em, they looked sound tho.I have not tried the other fuel tank yet. still need to out fit with primer pump bulb , and fuel line connector. About to place an order on that iboats site. I am hoping it was something weird like that phase separation or just an off mix. also the lake I had trouble at is at about 10,000 feet above sea level, the one I was at day before yesterday (when she ripped) was at more like 5000 feet. I am beggining to wonder if this has had any thing to do with it. The original owner (whom I got the boat from) lived on a lake at 10, 000 ft , so I dont know.....Boating in the mountains ! I have been told minnesota/wisconsin aside, colorado has one of the largest inland boating community's...

I seem to think the factory Jet size in the carb were about sea level to 4,000 feet but not sure. So its possible your running rich at 5000 and above if they weren't changed, who knows? Still should run though... Can't remember, did you change all the hoses from fuel pump to tank line connector on the motor. Also I read some guys had problems with there connector? If anything like hose or connector is sucking air your going to have problems. If its sucking air it might not leak gas so pressure test of lines would work, not more than about 3-4 psi max I think.
I have a old Station wagon that was a pain to start changed the fuel pump and didn't help much. then one day got under the car and removed the rubber gas line, put it in the sink, blocked one end with a finger and put a little air pressure on the other end, looked like a aerator for a fish tank but looked fine to the eye,LOL

Adding a bit of extra oil to the fuel is a good thing for the precision parts in the motor.

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In this case 18 / 20 ounces of oil to a 6 gallon tank is good to do.

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Ever wonder why ratios went from 24:1 to 50:1 overnight on the same motors ??--Does not seem very scientific !! ---It is all about marketing to make the gullible public think that a motor that runs on 50:1 is built a little better.----Fact is it will wear out sooner than a motor running at 24:1.

not all that true. the reason was the better oils that came out and all needle and ball bearings in them like merc had from the 40's unlike omc's with babbit and bronze bearings.i have NEVER had a oil failure with my merc's even nthe green tank onesat 50-1. 25-1 with 50-1 oil i use in my racing ones due to the High RPM's 6000 plus.

dave bernard wrote:

not all that true. the reason was the better oils that came out and all needle and ball bearings in them like merc had from the 40's unlike omc's with babbit and bronze bearings.i have NEVER had a oil failure with my merc's even nthe green tank onesat 50-1. 25-1 with 50-1 oil i use in my racing ones due to the High RPM's 6000 plus.

Yep, I was talking to a Merc Rep at a boat show that said the higher rpm race motors ran with lots more oil, think he said as much as 20:1 but not sure, might have been even more oil and this was less than 10 years ago. Think he said some motors would run over 10,000 rpm but my memory??? Isn't 50:1 a much different formular, I thought it was perhaps but don't know? I always use 50:1 on my 650 but mix more oil than 50:1, about 40/45:1, but think too much oil for sport boating will carbon up the pistons and cylinders prematurely? I never go over 5200 except for short bursts to 5600, can't afford a rebuild so careful

I'll post this FYI:

Mercury Bulletin Number 80-6:

"A. USE OF FORMULA 50-D OIL IN OLDER MERCURY OUTBOARDS

Formula 50-D oil can be recommended (at a 50:1 mixture) for use in earlier Mercury outboards regardless of year of manufacture.

Formula 50-D also can be used in other brand outboards (at a 50:1 mixture), provided that the manufacturer recommends use of a 50:1 oil mixture."

The above was copied verbatim from a Merc Service Bulletins Microfiche.

Since this bulletin was issued over 20 years ago, I'd expect that Mercury's latest oil formulations (and any good TCW3 oil for that matter) would be far superior to the Formula 50-D oil.

If anyone has any information where Mercury subsequently rescinded the above recommendation, please post a reply so we'll know.

Cheers..................ed


A caveat to the above would be that this recommendation was made for production motors. If you are racing or operating a "racing" motor, you of course should run a much richer oil mix.

i guess my memory is not that bad YET.

dave bernard wrote:

i guess my memory is not that bad YET.

I reckon we must still have at least one or two brains cells left firing up there, eh?

not far off.

Wonder if I have one cell left, thanks for that post, always wondered about using 50:1 in older motors with bronze bearings but not going to trust Mercury on oil mixture ...... I'll still use a bit more in all motors and use Seafoam every now and then...

Thanks for being so helpfull bill,
I have not changed all lines. I changed 1 line that runs between the middle carb and the top carb ,and also changed the line that runs from the seperator filter to the engine (as well as the seperator filter itself). The large input hose that runs from the gas cap near the transom to the tank does leak a bit when i fill er up. I plan on replacing it soon, its over fifty bucks tho..for 16 inches. I doubt this could cause any problems ? The diaphragms looked really good, however the fuel line connector (on the motor) is a great idea. i noticed it is difficult to remove the current "quick connect coupler". It requires a bit of effort, I thought it should be pretty easy ? Seems like a bad fuel mix is very unlikely here, if I was off it was by an ounce or less. After reading everyones posts in this thread I dint think that would be enough to throw me off. It was either that "phase seperation" or something else I havent gotten to yet. Mr Ferguson Poole Suggested the jet size as well, however the original owner lived and operated this boat daily at 10,000 ft. so I really dont think its that.....unless I need to have different jets for different lakes, but again I dont know about that, cause I know hes had it to powell as well and that is much lower that 10,000 ft. Do you use that seafoam as the package instructs or is there any special tricks to using it ?

Looks like your doing the right things but think your going to have to check and make sure every hose is good? If they are next might be cleaning the carbs again . I dont know how to check the fuel pumps for a air leak but someone should? Like others have said Do the cheapest and easiest things first and yes the fill tank hose shouldn't matter. SeaFoam? I have a couple cans but haven't used it much as the g3 is down for a few years. Redoing the interior and need to install a new water jacket for the 650. Seafoam is something you can use later, first get it running good. Did you test the wires. At dusk idle the motor and use about a 4 foot insulated wire, one end grounded to motor and the other run along all the wires surface, if theres a break you'll see a spark, don't get shocked, wrap one end to a old screw driver might be a good idea?

thanks again bill, I will try that test next time im out at dusk...hopefully manana, Is there any other way to test the fuel hoses ? I have checked by squeezing the primer bulb past the firm point, thats how I found the leaky line that I did change. Will that work for all lines , or is there a different way ?? The connector (male) and the hose that runs from the connector to the fuel pump would be a possibility. Is there a good way to check those with out removing (in the sink, station wagon style !)...Since that jazz is under the coils it seems difficult to access ? I have also been wondering how much a rebuild would cost (I have been considering doing that over the winter). Would I want to do it myself ?? Or is it beyond the DIY level ? I have rebuilt a car and motorcycle engine before. Its been quite a while though. Thanks again,
Jay

"She ran great !! top end roared with man balls!!"

So why ya talking rebuild if nothings wrong? These motors are quite simple really but if your not going to replace hoses for example that are near 50 years old your just going to go around in circles. You might be able to know if a fuel pump is good or bad but I kinda doubt it. If you had changed all that cheap stuff then if still a problem you'd know where to look next. If you dont want to change the fuel pump rubber diaphragm you'l need a very bright light like a led and twist and move the rubber around as u look through it, if you see a small speck of light, you've seen the light Thats how i found a bad one on a chainsaw but usually change those every few years as they stretch and wont start as easy. You might want to have someone hold that portable tank up high on the deck, then if it runs well you know its the lines or pump pretty much. If not its going to be condenser or coil perhaps, not much more left except cleaning the carbs and blowing out all the passages....

Hi,
My concern based on Bill's comments is if the motor is now operated at far lower elevations than with the previous owner. If smaller high speed jets were fitted based on the 10, 000 foot elevation and it is now operated in the typical elevation range for much of the country, then this could be a major issue.
As to a possible fuel system air leak, you could locate a portable fuel tank and fuel line assembly to test with, this could help isolate the problem. If there is no change with an alternate fuel tank/fuel hose assembly, an air leak would be located from the motor's fuel connector to the fuel pump. Note that any hose on the output side of the two fuel pumps has pressure, not suction for drawing air.
A fuel pump issue is possible if the diaphragms are stretched or hardened. If there is any question, frankly diaphragm kits are quite cheap. We sell them for $4.29 each.

Regards,
Joe
www.fergusonpoolemarine.com
This email address is being protected from spambots. You need JavaScript enabled to view it.

Glad you jumped in again Joe, I'm no expert like you but know the basics. Plus remember this that Jay said; ""beast quickly stepped up and roared to plane."" hard for me to understand it being Jets. I do wonder how a stack 6 acts with only 3 cylinders firing, will they run at all? If a coil winding is opening or shorting out every once in a while when things get warm could be it, ya think? IMO I think its best to replace all hoses, cause if the 50 year old hoses on the pressure side spring a leak (even though they may look good today) could have a nice BBQ and don't want that in the middle of a big lake on my boat If others want to chance it please take the camera as we all lov those pics of boats on fire

A friend had a '59 vett that we restored and every once in a while we'd stop and it wouldn't start for quite a few minutes. Then one day we were way out about 7 miles and went around a corner and dead, we waited and waited, nothing, found out it was coil of course.

Hey guys, Sorry I was curious as to what rebuild / overhaul costs. I am enjoying this fine piece of machinery and definitely dont want to spend a huge sum of cash to continue to do so, but do enjoy my gear in top working order and am a curious person. LOL. Just wonder what it costs , thats all. I having been working through some of the concerns in regards to the fuel system. I have had it out twice now since my last post. It ran really good both times , although the top end seemed to be a bit less than ive seen in the past.could be due to not being able to trim properly. I did notice in the first of the 2 outings that it had a more difficult time starting hot.Especially after a stall occurred. One of which was due to hitting some sand/mud !! But the second recent outing was at the lake that has shunned us before. It ran pretty much perfect at the 10,000 ft lake this last time out. I ran it for over 2 hours straight at various speeds before fuel got low and it started to sputter. I let er chill in neutral for a bit then cruised back to the dock on low speed fine. Hooked up my portable spare tank (outfitted with all new primer, line and connector) and went out for another hour ! ran great on the small portable ...only weird thing was that the primer bulb never would get real firm, .. whatever , worked fine.I have the connectors and line to replace the other 2 lines i havent done yet. I dont think the jets are a possibility , nor the fuel pump. I doubt it would run for the durations it has with a pump problem. However I have noticed what looks like grease of some sort coming from the starboard side square shaped port on the back side of the mid unit , just below the main tower.Also noticed it on the inside of the prop. When I went to add more gear lube (I try to add some every couple times out) water poured out of the fill hole then the oil, I let it all drain before I added more. This doesnt seem normal.The beast does have some greasy/oily areas on the underside of the main tower. Which is part of why I questioned the overhaul.I will order them diaphragms from Joe asap though, any part that goes for 5 bucks and can help/prevent problems is a great idea IMO. Thanks again to all who have been posting on this thread and site. Great peoples around here !

On a running motor the primer bulb will not be hard , nor does it need to be.---Many folks think that the primer bulb must stay hard, but that is not so.---It does sound like the lower unit needs new seals and perhaps work on rusted shafts where seals ride on them.---Sludge in the area of the prop may be normal for 2 stroke motors.

professor wrote:

On a running motor the primer bulb will not be hard , nor does it need to be.---Many folks think that the primer bulb must stay hard, but that is not so.---It does sound like the lower unit needs new seals and perhaps work on rusted shafts where seals ride on them.---Sludge in the area of the prop may be normal for 2 stroke motors.

Professor what you think about the lower and or top seal on the power head? or exhaust manifold/header on a motor of this age, should this be something to look at?

This sounds like a generally good motor to me and a overhaul is something you probably dont want to get into for no reason at all imo, if you had piss poor compression yes. Just need to figure out whats the issue, must be something small? I ran my 650 for one season with water mixing with gear oil but changed it after each outing till redoing the seals. Yours sounds worse than mine so when you get it running good redo the lower seals like the professor said/ As long as you've been changing the gear oil you should be ok, mine was fine with no rust and didn't need the stainless sleeve.

The lower seals on all those in line Mercury motors are basically the same part #----I have seen them completely shot on mid 1980's motors.

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You would loose crankcase compression on piston down stroke and suck in exhaust on the up stroke.

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Maintenance does not really cost anything it just saves you head aches and big overhaul money !

Thanks professor and everyone else. I am getting excited for the season. Glad I got lots of issues worked out last season with all of your help. I will be checking the l/u Seal kit asap. But was wondering what to do about the fuel tank situation. I have found that she really does not want to run for long on the regular gas tank.On the spare (portable) it runs great. I have replaced the lines that run from the tank to the engine. So would this mean that the seperator filter needs replacing ? I replaced it at the beginning of the season....OR do I need a new gas tank ? Thanks again

I have heard that some of these older motors have a hard time pulling fuel through these spin on water separating fuel filters. The pumps just aren't made to pull that hard. I would try to by-pass that filter temporarily and see if that takes care of the problem. I am assuming that when you are running on the portable tank it is not going through that filter. It could be as simple as changing the filter. I hope that helps.
Bill

I've heard that too Bill, about the ff/ws. I've been running one since 2008 without issue, but I do change the filter every year as preventive maintenance! (Make sure you use a filter rated for outboard use, as I've also heard of some "off-brand" filters not performing well with the gas/oil mixture running through them.)

I went back through the entire thread Disco, trying to refresh memory and glean as much knowledge as possible from the excellent advice given here. I know you stated that you replaced the fuel lines from the tank back, but have you cleaned out the tank and checked the pickup tube inside the tank? Just a couple thoughts, please pardon the amateur's intrusion.

I had a similar problem with my 1970 StarCraft w/ 140hp Suzuki, gave me fits of trial and error! Limped back to dock w/ friend constantly squeezing primer bulb! So starving for fuel??

Long story short (after going through all 4 carbs carefully myself, and was not the problem) I removed Suzuki quick connect fuel line from top of fuel tank. #2. took a wrench and removed male quick connect fitting, turned over fuel line fitting and looked into treaded end, looked like black debris up in there. Inserted a piece of wire in to it and came out with BLACK GUNK! Where in the hell did this crud come from?! It came from the inside of the old black rubber original equipment vent hose... slow deterioration dropping rubber particles into fuel tank. Removed fuel from tank and filtered, cleaned out fuel tank.

Replace or clean fitting, replaced ALL fuel line from tank to engine and between carbs. Some carbs have plastic fuel fittings, be careful. I used a razor knife and cut a slit in fuel line over fitting, then gently remove.
Replaced vent hose. Problem over! : )

BTW I have never used regular fuel w/ 10% ethanol. This was just an old age fuel/vent line issue. However, as you might already know, use of 10% ethanol fuel WILL ACCELERATE this kind of fuel system mess for a number of reasons on boats, all small engines also!

Some gas stations in my town sell NON ETHONOL premium fuel, or I buy at the fuel dock.