TOPIC: 1965 Mercury 650 problem

Hey Guys
Newbie here. I've got a 1965 Merc 4 cylinder 650. She's well taken care of but I have a miss or sputter at idle or very low throttle. When I open it up she sounds and performs great. I've also noticed when I run her with muffs, she won't do it. Only in the water will this happen. I can't figure it out. It actually stalled out on me approaching the dock. Any insight would be greatly appreciated.
Also what prop should I be using? I have an old 2 blade speed prop on there now, but would like better performance out of it.
I'm very happy I found these forums, as I have recently become an old boat junkie. Thanks much in advance...

Welcome aboard! This a great forum for everything Old Merc's.

Can we get a little more background on your motor? Is she new to you? Or you've had her for some time and this is a new issue. Also, have you ever been through the tune up process (cleaning /setting points, adjusting pick ups etc)?

New to me. I just recently changed plugs, impeller gear case oil, etc. I was under the impression you needed a special tool to pull the distributer and unthread the plug wires. I did noticed a nicked plug wire that had electrical tape wrapped around it. I noticed this checking compression, which was 130 even on all cylinders. All wiring is in excellent condition except for the nicked plug wire.
How hard is it to change/ check points and change the plug wires? Will these cost an arm and a leg? Do you think that may be the problem?
Thanks in advance-

it has a magneteo on it not elitronic. just drop the mag and clean it up set points .008-.010 and clean the cap and rotor.any problem call me 1 914 310 7086.

Atta boy Dave. Karma to you.
And welcome ahoy. Post some pics of your rig, we are curious.
Neil

I agree with Dave and if its a slight miss you may find its one plug wire acting up. you can use an ohm meter to check the resistance from the cap to the plugs to find the bad wire but, best you remove all the plug wires clip a 1/4 off both ends and reassemble the plug wires, to ensure all connections are new and good

also do yourself a favor and bench test that mag before installing to make certain all is well, If your in doubt about this I made a video how to bench test for my buddy, holler if you need to see it

Michael

I have found that the contacts in the rotor cap are over looked
clean them well and use good grade solid wires
Charles

You guys are awesome. Thanks for the responses.
Now, is it just the 4 bolts to drop the magneto, then the standard head screws to take the cap off. Im learning as I go, so layman terms and a little verbal tutorial are best. Maybe a pic if it's not asking too much.
The last motor Ive really done anything to was an old 50' flathead when I was 20. That was like working on a lawnmower engine. This is a learning curve.
Also, that bench mag test video would be great.

One More..The Molly B

Molly B is looking pretty good there Matey, from the "sneak preview". We're looking forward to seeing more pics of her! (It's what helps us get through the "off-season")

Nice CLEAN Boat A.M. Is that a GLASSPAR.?? The MERC is so clean inside beloongs in a museum , not on water ..!

You will find real quick ONE of the cap bolts needs a Off- set open end wrench 3/8 or 11 mm something in that size to un bolt,, BUT kept a few of the Merc helpful wrenches.

Yes, she's a Glasspar. 1965 Avalon. She was kept in a garage her whole life. All original, just finished painting the interior.
The motor is immmaculate, a little paint scuff on the skag and prop and thats it. Very clean inside, and the little lead tags are still there.
It was a second owner boat. The guy before me bought it off his friends dad, who barely used it.
Im very happy with her, my 3 year old son loves it even more.
Lucky for you guys, we dont have an off-season here in San Diego, so I will post pics soon.

I really appreciate all the help. I'll pull this mag and distributer soon and see if that does the trick.

I made this Mercury 4 cyl Magneto bench test video for a buddy of mine .... he kept re installing the mag to check it and after several attempts he emailed me sooo pissed, I felt a vid would make him feel better and it solved his problem because the mag I used for the video also had a low speed miss

Of course I could have just torn down the mag , rebuilt it in its entirety and be done with it but I like to learn why and what causes my issues before I overhaul them

hope this helps you

PS. youtube waters down the video throwing away frames, so when you see the Merctronic sparking test trust what Im saying not what you see

I don't have anything to contribute. I just thought my avatar with the bitchen 950 Merc would look great in this thread

Michael, you over did yourself again. Great video.
Cal

HopFrog....THAT was FUNNY! Spit my coffee on the monitor.

MadProp - Excellent video. It made me realize I should set something up to test my Pertronix Points conversion set up vs sticking on the motor, then the boat in the water, then float away when its a failure (ok so I'd test it on muffs). Where does one get one of those neato testers?

peterstransky wrote:

MadProp - Where does one get one of those neato testers?

Peter I have never seen one for sale anywhere, I have several Merctronic tools from my Harley shop days, we could buy many electronic testers dial indicators etc etc built by Merctronic
from the SnapOn or maybe Mac truck that came around every week

anyways I anticipated my buddy asking the same question so the last frame of the vid shows him how to make his own, the one thing I missed to improve the tester was to cut the tangs of the spark plugs so the spark is forced to jump from the electrode to your negative adj jumper bar

Here's a Super-Whamodyne spark tester mfr'd by CDI Electronics, not cheap but looks like a quality unit. I found it for under $50 at this site:

www.shopboatpartsonline.com/cdi-spark-tester-511-9766-p-78.html?utm_source=GoogleBase1&utm_medium=BaseFeed1&utm_campaign=products

$51.26 from Boatfix.com from which I've ordered many parts:

www.boatfix.com/bykeywordnew2.asp?textfield=511-9766&texttype=2

The other site has decent prices but haven't heard much about them, anyone done bizness with them?

The Good Dr. Frankenmerc made up a nifty tester, just a line of spark plugs welded to a metal bar. Use a ground strap with clamp, from the bar to motor. Break or grind the side electrodes off the spark plugs, and if the spark can jump that gap it's plenty hot.

Here's a very simple KD Tools spark tester:

www.amazon.com/KD-Tools-2757-Calibrated-Ignitions/dp/B0002STSB2/ref=pd_cp_hi_0

I made some inexpensive substitutes for this tool with an extended-tip spark plug w/ground electrode removed, and big clamp. Works OK but a tester with multiple taps would be a lot easier to use if you're working on Fours and Sixes.

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

peterstransky wrote:

HopFrog....THAT was FUNNY! Spit my coffee on the monitor.

<emails peterstransky a roll of paper towels>

It was 2:00 am and I should have been in bed lol

I really was thinking "I have nothing to contribute", the rest came out of my fingertips while I was dozing off.

I so respect the old school troubleshooting going on here in FG as I so much suck at it. This thread set me straight on a few things. I'm new to motor boats really. Grand Daddy got me going on V8's as a teen and I got into motor cycles in my 20's. Converting my car knowledge to outboards finds me at a loss. So many things are different. Strangely enough, much simpler. Reminds me of the few airplanes I've been around; i.e. magnetos and all.

Thank you all who contribute brilliant instructions to the Lamenites out here.

If you remove the throttle stop/idle stop/spark stop plate at the front of the mag, you'll find getting to the back bolts on the mag a lot easier.

Note that you shouldn't mess with the screws on that plate, they're secured by lock nuts for that reason (until it's actually time for an adjustment!).

The plate is held on by (2) bolts at the top. In your picture of the mag, there's a non-factory red wire being secured by one of the bolts. I'm assuming that's a ground wire installed by a previous owner.

If you still have trouble accessing the back mag bolt, pull the distributor's swivel/link rod assembly off the throttle arm. It's held in by the 1/4-28 nut and is a body-fit type, so the best way to get 'er free is to loosen the nut until the end of the threads is flush with the nut; then carefully tap the nut until the link rod assy breaks free from the throttle arm.

After that you should have no trouble getting at those pesky mag bolts.

HTH.............ed

Hi,
Sears has nifty 2 end wrenches with a curved handle between ends. This wraps around the distributor very nicely to get the back bolts. I think it is a 3/8 on one end and 7/16 on the other, it is the closed style ends with notches rather than a hex to grab the bolt head. I have one in my "Merc" only tool box.
Where the motor runs so good at high speed you might want to check the idle misture and the idle speed. It is still a good idea to clean the points etc.
WOW is that boat clean, I like that model Glasspar, great find.
the transom top is bare plywood on top so it might be wise to take parts off to get at it to seal it for the longterm, it is a common point of water intrusion eventually rotting the transom. Same with theose lower enging mounting bolts and the speedo pick-up if there is one.
Randy

Thanks guys for all the comments and advice. Its all been helpful. Ill have a report back in a week or two, hopefully she'll be running like a top.
Now all I need is a meet or cruise in the area. Excited to get my son and I out on the water.

-Ahoy

Dave-
you hit the nail right on the head. She is running great. No hiccups and I ran her hard to see what she could do.
Took advantage of the 78-80 degree weather and took it out on Mission Bay. Seriously couldn't be happier.
thanks all for the input guys.. Hope to see you on the water...
I'd like to try and organize some kind of meet here in so-call, wonder if anybody would be interested?