TOPIC: 1978 Merc 1400 questions

You are running too lean. Turn the low speed adjustment screws on each carb out (CCW) 1/4 turn and try again. If it still falls flat, back them out another 1/4 turn. Repeat until it is able to take the load on take off. Refrain form reving it on the muffs, bad things can happen.

Great! Thanks for the info, I appreciate it. I assume I should tie up at the dock to do this or do it while on the water and just stop between adjustments?

Do it out on the water so you can check the holeshot without pulling all your deck fittings out!! When that beast lights up correctly it will PULL big time, assuming you are propped correctly that is.

Agree with
Alacrity, when it goes you want water in front of you to enjoy!

Ok, great, will try to get it out on Saturday morning for some testing.

Took it out on Saturday, same issue: would run fast with no load. I tried adjusting carbs to make richer but made little progress. I decided it's time to take it in to the local dealer to see what they can do with it. I think it's worth it at this point since I saved by doing all the other work on the boat myself.

So, dropped it off at Cooper's Marine, Ashland, VA. We'll see what they say!

Jerry Cooper worked on the engine and said the compression was good, did a tune up of the 3 carbs. He said it was too lean.

Got it back from Cooper's last Thursday, took it to Ancarrow's Landing (the once site of Ancarrow Boats in Richmond) for a test.

So, the engine ran much better at idle, not as rough as before.... but... still when giving it throttle it would not rev up and would cut off with too much throttle.

Jerry asked about the prop and I told him it was a new 19 pitch.

So, looking at the other thread, maybe it's the fuel pump diaphragm? But it will run at a high rpm if not in gear.

Ken

Most motors will wind up in nuetral because of no load.

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A " tower of power " will wind up on 4 cylinders.

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Testing with no load proves nothing.

That fuel pump is a little different than the ones I've rebuilt Ken, but they're pretty easy to put a kit in usually. Just watch which way the check valves are installed when you pull it apart, other than that it's just gaskets and a diaphragm, I believe. You can do it.

(Not sure that's your problem, but it isn't going to hurt anything to do it and the kits don't cost that much = peace of mind.)

Ok, I agree about the fuel kit: I got one off of Ebay and it came in today. It is easier to replace the small, inexpensive, obvious things before going to the expensive, difficult solutions so I'll try this.

Thanks for all the support, you all. I'm sure it's something simple and this may do it.

Ken

After all this time, I am still having the same issue with the 1400! Here's what the symptom is:

Engine will not accelerate when under load.

Here's what I have done:

1. Rebuilt the fuel pump.

2. Had the local dealer look at it twice. First time he checked compression and tuned it. I had told him the symptom. Didn't fix.
Took it back, this time he checked the compression again (he had mis-spelled my name and couldn't find the paperwork) and then he found a fuel leak on one of the lines. He put the engine on his "dynamometer" and said he got 140 hp. And that he thought the problem was solved.

I took it out today, with much anticipation and yuck! It is hard to start, doesn't idle, when put in gear, have to give it nearly full throttle and it runs rough and at a slow cruise speed.

How can I test this problem while on land? I'm getting tired of launching it to find it still has a problem. I have a 55 gallon steel drum. I just don't know if it's wise to put an engine of that horsepower in it.

I plan to call the dealer on Monday and see what they are doing: it doesn't seem like they grasp the issue, if it's doing the same thing after 2 visits and a bunch of cash.

are your controls adjusted right?

At one point I had taken the controls apart and put them back together incorrectly. But now I believe they are: Forward, Reverse and Neutral work, the choke works, and if I press the override button, it will run at higher rpm in neutral.

I just read online that it's not a good idea to put the engine in a 55 gallon drum, maybe only if you have a test prop, one that creates drag but doesn't propel the boat.

I read a few more threads and some suggestions were to check and re check the fuel lines.

Ken,
I'm really sorry to hear that you are having such a tough time with the 1400.
Sadly - I don't feel like I have read enough specific info to try and throw out suggestions yet.
One thing that works better than use of a 55 gallon barrel is to secure your boat's transom to the trailer real good, back into a boat launch until the water level is well over half way up the transom, lock down the tow vehicle so it won't budge, and start the beast and tinker with the idle until it works right.
Prior to doing this though, I have found that patiently working through the carburetor to ignition syncronization process will make a huge difference in the final outcome.
After that you can focus on setting the idle jets and then the idle RPMs at the boat launch.
Granted - there may be rules restricting such activity at your local boat launch so be aware of all the rules before proceeding.
Revving the engine in Forward gear during this procedure can result in severe damage to the gravel supporting the boat ramp, but there is no reason to rev the beast in gear under these circumstances.
Thom

Thom,

The local ramps are usually pretty busy but I may be able to find a time when it is ok to run some tests.

I have found that doing diagnostic work in any medium can be frustrating, especially when it's unfamiliar territory. And when it is a compound problem, ie, more than one cause, the frustration and confusion for the novice is increased exponentially. That is the situation I feel I'm in.

Basically, that is why I took it to a local dealer, to pay for his experience. So far, his work has been to tune the engine, check compression and test it on a dynamometer. He thought he had the problem solved.

So, now my problem of having a lack of knowledge and then putting it in the hands of an experienced mechanic has added to the complexity.

I don't know at this point if I should try to fix it myself, potentially "undoing" what work he has done, or take it back to him.

Ken

Find the local shop that has a MARINE DYNOMOMETER !!

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See if the 140 HP is just the decals or if the motor is putting out proper horses at the propshaft !!

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No adjusting will fix a motor that is in " poor shape "

That is exactly what Cooper's Marine has and as he said last week, he tested it on. He got 140 hp or so out of it. And he thought the problem was solved.

Must be water in the gas then.

I have a small 3 gallon test tank and have filled it several times while testing. Cooper thought it might be bad gas at one point but I put new mid grade in last weekend before going out for the test run.

Could be as simple as a fuel line problem. Have you tried different lines? Has the fuel tank vent been checked?

These are very often found to be the problem after chasing after a lot of other things.

The dealer found a leak the last time and he thought that it was fixed after that.

Here's one symptom: after I get it started, if it starts to die, I can push the choke and it will rev it back up.

But there may be another leak somewhere.

or richen up the idle.

was the fuel pump diaphragm ever replaced? be sure the fuel line from the tank to the motor is good. The primer bulbs can cause problems. Be sure you physically look at all of your fuel lines to be sure they are secure.
Sounds like you are having to choke to draw fuel into the motor so check the fuel pump, check for clogs in the carbs amek sure your fuel lines are not falling apart from the inside out.

vent in tank you said you are using a small test tank. I know that my 400 will not run at above 3/4 throttle very long unless I am actually running the Mercury fuel tank. or completely remove the cap from the Atwood tank. I will bring that up in a different discussion.

loose that Atwood tank they can be problematic.

All good points! I now have a plan. We know it's a fuel issue so I'll start from the outside and work in. So, I'll take the 6 gallon tank I use on the Feathercraft and put the Mercury fitting on that (it has the newer fitting used on the Mercury Mariner). I see the logic, ie, that it could be that the small tank and vent cap doesn't allow enough fuel to get sucked through.

As to the fuel pump: yes I did buy a rebuild kit and installed about a month ago to try to eliminate that possibility.

So, I'll try the new tank first.

Ok, so went to take it out yesterday with a 6 gallon tank that I know works. Part of the old trailer fell off on the way (thanks to the lady who let me know!), so went back to the house to change the rear rollers to bunk board.

So, today had to take the constructed bunk boards down to the river, put the boat in, go up to the parking area to remove the rollers and replace. Operation successful.

Decided to try out the tank while there. The result was the same, maybe a little better but the major problem is still there: won't take gas under load.

I suppose the next step it revisit the fuel pump and fuel lines. If that doesn't do it, what's next the carburetors?

Pull the carbs and clean them out. This includes heating and brass screwed in and glued in plugs with a small propane torch. My 74' 850 had them same symptoms. We pulled the carbs the second time and took out those brass plugs to find a jet with a tube attached in each carb that was totally plugged up. These sit just back behind your mixture screws and won't allow the correct mixture if plugged. Carb cleaner and wire or a torch tip cleaner will be needed.

SS

Thanks, I'll do that.

Should I buy a rebuild kit for these? I had removed them and had them cleaned by a car friend and he said they all looked ok, ie, gaskets, etc. If so, this looks like the one to get:

www.wholesalemarine.com/p/1395-5109-1/Repair+Kit-Carb,+Mercury+-+Mercruiser+1395-5109-1.html

Wow this sounds like the same thing my friend Paul went through recently on his freshly rebuilt '86 115 Mariner. (I think he could have wrote this post!) $150 at one shop, $200 at another, problem was still there. The repairs at your shops sound like the same repairs done to his boat. I had a chance to look at it inbetween shops visits and did find water in the fuel which was taken care of before the second shop visit. When I finally had some free time to look at it again after the second visit to the shop. I removed all three carbs and thoroughly cleaned them as SS has described, put it back together, fired it off and set the carb adjustments on the muffs in the driveway. The next time he took it out it ran perfect and has been all summer long.

You may need a carb kit but it will depend on what the gaskets, floats and such look like. Take your time pulling the carbs if all goes well you should be able to save the base gaskets and the rest of them. Mine came off just fine. I gonna bet your in the same "boat" I was in, mine ran what we thought was really well in the driveway same as my buddies boat with his mariner. Put a load on them in the water and they didn't have power. Clean every port you can find even the hidden ones behind those brass plugs and you'll be set. Say be careful when spraying the carb cleaner, wear safety glasses cause you'll do what I did and spray in one hole that you goes through to the other side only to find it comes out in another spot and hitting you in the face!! We've put about 200 miles on my boat since cleaning the carbs and it's running great. Also get some Stabil and start running it in every tank of gas. My gas mileage has improved since doing that as well.

Can't wait to hear the results.............Keep us up to date.

SS

I'm looking forward to taking them off and checking them. I'll get the kits if I see any problems. We had cleaned them before but they could have gotten fouled. Or possibly we didn't catch every area.

Thanks to all for the ideas, this could be it!

Check for missing " bleed inserts "

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Take bypass covers off and check them ( 5 inserts on your motor )

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Outboard carburetors are very simple and usually just a gasket required for bowl cover.

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Your " boost venturis " are all in place ??

To get any of the Brass plugs out simply make sure the carbs are empty of fuel. Carb cleaner and an air compressor will take care of that. Then put on a good leather work glove and grab a small propane torch. Just a small flame is needed, heat the aluminum around the plug and not the plug. Your going to be melting or burning out the glue they use to hold the plugs in. If you don't heat them you will strip the plugs screw driver slot out!!

SS

After work today I came home to take the carbs off. Whew, that was a job! Had to take the starter, top plate, front plate to get to the 7/16 nuts. Then getting the nuts off was really difficult, very hard to get a driver on them with an extension! Is there some trick to it?

I did finally get them off.

Yep it's about a 2 hour job. My 850 had to have the front plate, top plate, and the starter removed. Then take a wrench to the top carbs nuts, then the bottom carbs nuts. Install in reverse order making sure you put the bottom carb on the whole way before you even start the top one otherwise you can't get a wrench on the nuts with the top carb set in place. Once you've done it a couple of times it's pretty easy.

SS

I have found the easiest way to get carbs off is to remove the float bowl covers with the carbs on the motor first, leaving the fuel lines connected. Once the small screws are removed you can lift all three together up to get them free of the bowls, be careful not to bend the flat tabs in the process. Place all this stuff to the side and it makes access to the nuts on that side of the carb much easier.
Where you are redoing the carbs I would replace the fuel lines at this point so you could simply cut the old ones between carbs to ease the removal of the covers individually. I generally reasemble the carbs to the motor then install the covers and then install the fuel lines when rebuilding and replacing lines. Cut the new lines to length between carbs using old lines as a guide of measuring once the carbs and bowls are bolted on. Merc used zip ties for hose clamps in the later 1500's, not sure about the 1400 but they work great.
If your lines have factory crimped fittings and the hoses are OK I would not cut them, just keep this all together as previously mentioned. I have not found an issue with the fuel line Merc used and Etahnol fuels, but I think others have. It is a lot harder to redo made up lines than ones simply with the ziptie hose clamps so save the work in this scenario. My opinion only.
One thing is whether you keep all the bowl covers connected by the fuel line or not, a VERY IMPORTANT thing to pay attention to is setting up those two tabs on the needle and seat that the float engages. This sets the fuel height in the bowl and determines the correct high speed fuel mixture. The fuel height in the bowl determines the "head" on the main jet.
I have not had problems with older floats and ethanol fuels but floats are cheap so I usually replace them to be sure.
Open end wrenches are the best as sockets are a hard fit and you risk rounding them off but it can be done. The front and top cowl support, plus the starter should be removed for best access.
Good luck, Merc sure jammed everything in so it' a bit of a Rubik's cube sometimes to get things off.
Randy

I got the carbs apart this afternoon. The brass fittings and the 2 tubes were more difficult, I ended up whacking the large ones on the bottom with an impact driver. The brass tubes that lead up to the venturi were clear and the small holes in the sides were open. I used a nylon "b" string from a classical guitar to test the openings.

So, this is what I was afraid of: I wouldn't find anything and I'll put it back together and it will do the same thing.

I'll see if I can figure out how to adjust the floats by looking at the Clymer's manual I have.

I did this procedure almost exactly as Randy described. I had less than an hour to R&R the carbs themselves not including cleaning them. Taking the float bowl covers off 1st allowed me to use 1/4 drive 6 point socket to remove mounting nuts on the carbs.I used a 11mm socket as it fits the nut a little tighter and less likely to fall out of the socket. I did not remove the starter, just the front plate.Nice to have small hands to get into tight spaces. I had an extra set of hands to hold the fuel bowl covers in the approximate position while I re-installed the 3 carbs. I did replace all the fuel hoses including hoses to and from the fuel pump,fuel enrichment system. I had previously replaced all 3 needle & seat assemblies and floats.

I had have a similar issue as Kensikora so have been following this thread intently. I hope to see if I corrected my problem in a day or so.

kensikora wrote:

So, this is what I was afraid of: I wouldn't find anything and I'll put it back together and it will do the same thing.

I can relate. I found no smoking gun and these are pretty simple carbs.