5 Hp Sea King Clinton misfiring?

[Mark Akimoff]

I have a J500 Wards Sea King by Clinton. I purchased a service manual copy from Discount Marine and basically performed the Major Tune-up. This old motor fires up and will run great and then suddenly (and completely randomly) misfire and sputter out. When I was overhauling the carb I noticed that it was pretty warped across the face where it bolts to the intake manifold, but that a fiber gasket and a thick metal and ?asbestos? gasket seemed to be sealing it. Could an air leak here be the problem and why would it be completely random-The? carb is a walbro LMB 153 which all the good mower shops in Portland say are out of manufacture and impossible to find. Some suggested filing the face flat, has anyone done this and what are the secrets to it?

Thanks,

Mark
Portland, Or

 

[steelespike]

Re: 5 Hp Sea King Clinton misfiring?

I think I would put some emery paper on a flat surface
like an old piece of glass and carefully sand it down by running the carb over the emery.The powerhead is air cooled but the leg is water cooled water should mist out
of the relief holes in the leg.If not the motor may be overheating.When it sputters out check for spark.You might try a squirt bottle of fuel mix to see if it will stop it from stalling.Or try a little choke.If it helps that indicates a fuel supply problem.
My guess is the carb flange is not the problem.Be sure the points are set correctly sometimes the rubbing block will wear prematurely and cause the point gap to be too small.causing problems when they heat up.
I wouldn't put too much money into this motor as they are marginal; performers.And as you probably know Clinton has been out of business for some time.

 

[Mark Akimoff]

Re: 5 Hp Sea King Clinton misfiring?

Steelespike,
Thanks, here is an update. I did manage to flatten the carb face, using a bastard file at first and then emory cloth on glass. As you suggested this was not the problem, although it does seem to idle better now. The points are brand new from discount marine but they did seem to have a sloppier fit compared to the old points. I will tinker around with that and see if it gets me anyware. I suspect the problem is in the fuel system as the mixture needle really has no effect on the running and in fact needs to be firmly seated all the way in to start.
This is a very simple motor and easy to work on, but I can see from the machining on them that they were cheaply produced and it would make sense that they weren't top performers. Does the quality change at all with the higher horsepower models? I ask because I saw a 12 hp 1970s sea king listed that would probably be better size for my boat anyway.

Thanks,

Mark

 

[steelespike]

Re: 5 Hp Sea King Clinton misfiring?

Without a model number it is difficult to know for sure who built them.Most likely Chrysler/Force.Better trhan the Eska/Clinton motors but not without their problems
Parts are limited especially the older stuff in the 70s when they were still Chryslers.Force built are not much better but some Mercury dealers carry Force stuff.Though some time ago they anounced they were dropping Force parts support so no new stuff coming into the system unless shared by the Merc line.
There is a reason you see Chrysler/Force McCulloch Clinton/Eska etc. less costly than say an Evinrude.
Parts support and appaerent reliability.
Evinrude/Johnson and Gale from the mid 50s to present date are relatively bullet proof and routine parts are still readily available.
Even right here on iboats.