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Johnson Seahorse 2.5hp issues . . .

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brj8832

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Workin on a 1947 Johnson Seahorse 2.5hp Question is, what kinda compression should I be getting? Also this motor, after it sits overnight, when I start it it will run for maybe 10 sec. then die! :mad: Then will not fire again unless it sits for awhile. Got great spark, compression is 50 psi. I know the fuel is making it to the carb. but unsure if it's going any further than that. Do these motors use reed valves and if so where are they?!?:confused:
 
Don't think it's a float issue. When I turn the fuel on you can watch the stem of the float rise through the body of the carb. And when you touch it it returns to its normal "floating" position. Maybe a passage between the float and where it's drawn into the engine?!?
 
This is what is called a " 3 port engine "---------NO reed valves at all.--------Runs off a rotary valve on the centre bearing and that simple needle valve there adjusts the low speed mixture.------------Have you checked filter in the tank outlet ?
 
Yep, checked for spark with a "spark checker". Can't get any better (new points and condensers). The float is made of cork. Took it out let it sit in a container of gas overnight thinking it was maybe getting saturated and then sinking. But the next morning it was still floating! Racerone, which center bearing are you refering to? Also, the shaft that goes into the carb that adjusts rich/lean and you push as the primer. Does that have any kind of gasket or o-ring at the top? This one doesn't and leaks alot of fuel around the shaft where it enters the carb body?
 
There is only one center bearing and there is a hole going in to it.--------Rotate the crankshaft while looking into that hole and tell me what you see.------------The wee copperline coming down from the carburetor feeds fuel to that hole and it has an adjusting needle.---------Carburetion in it's simplest form !-------The primer likely has a leather washer as the pumping element, remember this is 40's stuff.----------A very nice simple durable motor.----There are lots of them around and usually at meets you can finds gray haired experts on them
 
It looks to me like the crank turning (definetly something moving). And yes, I've also noticed a spritz of fuel coming out that hole when priming. Is there a standard setting for that needle valve? Most small engines if you set the needle valves 1 1/2 turns open from the fully closed position that'll at least get em going then fine tune from there.
 
It also has 2 holes leading to the 2 crankcases for low speed air fuel intake.----You adjust that needle for best / smoothest idle.
 
So . . . with that being said. If when starting it just revs up and dies would you tend to think it might be set to lean???
 
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