1976 25HP Johnson choking on low speed

[andreipou]

Hello,

I have 1976 25HP Johnson (model 25R76E).
It was loosing power on high speed.
I took it to mechanic and he said it was leaking some air thru the crankcase seal so I:

1. Put new seal without disassembling crankshaft and pistons
2. Rebuid carburator using new kit plus other small things

I did it myself because shop cost would be more that a motor cost.
I have some mechanic expirience, but I am not so good with diagnostics.
I followd the repiar manual step-by-step guide.
Timing was done using "static" method with 0.02'' point gaps.

Cam was tuned using 2 marks on a cam.

Now it runs fine on high speed but chokes idle.

Mechanic says compession is good, spark is good and he does not see why it chokes.


Any clue would help.

Thanks.

 

[tashasdaddy]

Re: 1976 25HP Johnson choking on low speed

read this single needle settings. http://forums.iboats.com/showthread.php?t=167352

 

[andreipou]

Re: 1976 25HP Johnson choking on low speed

I tried this for 2 hours.

When I put tiller handle on "SLOW" (the cam roller goes between two marks on cam and carb throtle just closes) it runs for a while seconds but then stops.

Only if I open needle to run very high rpms it does not die.