1964 5.5 hp Evinrude Fisherman - intermittent motor problem

Hello all,

I have been having some intermittent motor issues lately. The motor seems to run at about half speed, so I changed the plugs and it seemed to work. However, within an hour when I powered off the motor and attempted to restart it, it was back to half speed. Went back with my trolling motor, and an hour later started up the motor and it ran fine...until it came time to start it again. I hoping someone here my know what exactly is happening with my motor - I really thought it was my plugs as it happened before (the half speed thing) and it fixed it, but this time no such luck.

Any thoughts or ideas to help diagnose my problem would be greatly appreciated!! If more information is needed, please let me know and I'll provide that.

Cheers,
Paul

Re: 1964 5.5 hp Evinrude Fisherman - intermittent motor problem

Possibly you are fouling your plugs. 1/2 power usually is the result of losing one cylinder. What spark plugs are you using?

Re: 1964 5.5 hp Evinrude Fisherman - intermittent motor problem

I'm using J4C (what I took out after buying it). There is a lot of residue in the plugs, even when putting new ones in there.

Re: 1964 5.5 hp Evinrude Fisherman - intermittent motor problem

A good place to start is by doing a compression test on your engine to be sure it's in good mechanical health.

After that you need to start thinking about if the ignition system is up to snuff. Use a spark tester to see if you are getting good spark. The ignition should be able to generate a hot blue spark that can jump 1/4 of an inch or better. If not, you need to take a look at your points, coils, and wires.

Carb adjustment may also be a bit fat, and need some tuning.

Lastly, what oil ratio are you running?

Re: 1964 5.5 hp Evinrude Fisherman - intermittent motor problem

Thanks for the info! I did the spark plug test and have a good spark. I have heard in the past that as coils go they can act like mine are acting (i.e. good when cold, bad when hot), is there an easy way to test a coil without replacing them? My ratio was 30-1 until I noticed the build up of residue and cut it back to 40-1.

Thanks!

Re: 1964 5.5 hp Evinrude Fisherman - intermittent motor problem

boater321 said:

Thanks for the info! I did the spark plug test and have a good spark. I have heard in the past that as coils go they can act like mine are acting (i.e. good when cold, bad when hot), is there an easy way to test a coil without replacing them? My ratio was 30-1 until I noticed the build up of residue and cut it back to 40-1.

Thanks!

Click to expand...

Someone may be along with some figures on resistance checks for the coils, but honestly if you can visually look at the coil, most of the bad ones are cracked. You can pull the starter assembly off, then pull the inspection cover in the flywheel to peek inside, but it also may be worth pulling the whole flywheel for a better look, especially if you haven't been there before. Even if you find the coils are good, with the flywheel off you can clean or replace the points if need be.

Your engine *MAY BE able to run on 50:1, just as long as you are using TCW-3 approved 2 stroke oil, and not air-cooled 2 stroke oil (such as the oil used for weed whackers, blowers, chainsaws dirt bikes, etc) .

*Edited till 100% correct info is known

Re: 1964 5.5 hp Evinrude Fisherman - intermittent motor problem

Thanks again for the information! This afternoon I will take apart the flywheel and see what I can see, I hadn't thought of just lose/bad connections. Perfect on the oil - I am using TCW-3 so I should be good on that, but good to know I can go back to 50-1 too.

Reallly appreciated your time with this. I will updated as soon as I have it back together.

Cheers

Re: 1964 5.5 hp Evinrude Fisherman - intermittent motor problem

boater321 said:

but good to know I can go back to 50-1 too.

Click to expand...

Hold off on switching to 50:1 for just a bit. Let the guru's chime in on this one. Just took a peak at the engine parts diagram, and your little 5.5 may not be a full roller engine (may require a bit more oil).

Re: 1964 5.5 hp Evinrude Fisherman - intermittent motor problem

I think your motor was originally spec'd for J4C, but for some reason OMC changed the plugs to J6C.

http://www.boatsetup.com/Spark Plug Chart 2007 BRP.pdf

If you do a lot of trolling, I suspect the J4C would be more suseptable to fouling (colder plug). I use J6Cs in my 1961 5.5Hp and have never had a fouling.

The second thing I would do is take a look at those coils and make sure they are working well. A plug spark test is not the same as a true spark test. Use an external tester and make sure your ignition can jump a 1/4" gap. If not you may not be getting proper combustion causing intermittant loss of a cylinder as well as plug fouling.

The third thing I would do is a proper carb adjustment for your rich/lean knobs. If you are too rich, that will also foul the plugs. I would also open up the T-stat section and make sure that the stat is there and working properly. If you motor is too cold, that will not help the spark plugs very much.

Lastly, when you get this issue resolved, plan to do a decarb. You can search this site for the procedure. Whatever was causing your cylinder to drop off, you can bet the unburnt carbon is still in there and you will want to blow it out, sooner then later.