28hp woes

[quackaddict1]

Hello all, after I thought the worst of times were behind me it seems that this Johnson motor I have inherited hates me. I was given a 1995 28hp Johnson, it had been neglected for some time, to make a long story short, I have replaced or put kits into the carb, fuel pump, both intake gaskets, all of the lines in the motor and now use a new fule tank and external line. Basically the fuel system is new. After these parts the motor ran fine for the most part, started, idled, and ran at WOT, but had a cough between 1900 and 2500 rpms (as measured by a tiny tach) So suspecting dirt in the carb in one of the circuits, I removed it and cleaned, then replaced, In the tank that night it ran great, wound up (under load) started and idled, I thought great, got it licked.

So now to my frustrations, I take it to the lake saturday, and it starts, I idle out to deep water and I go to wind it up, get to around 2300 rpms and it bogs down, with the throttle all the way forward I still got around 2300 rpms. WTF? SO I put it back on the trailer and take it home after the weekend, tonight, I have torn apart the carb three times and it still acts the same, starts and idles fine then dies at higher rpm, it will wind up for a couple seconds then die from a lack of fuel. With your hand acting as a choke it runs great, all the way up as it should. Do I have a seal leaking? My father and I are thinking crank seals but haven't put together a pressure tester for the motor yet. Is there something I am missing? The primer ball stays hard throughout, and there are no visible fuel leaks in the fuel system.

Is there an easy way to access the exhaust side crank seal to test it?

 

[tashasdaddy]

Re: 28hp woes

linc n sinc of the spark and carborator. if they both are not advancing at the proper coordinated time, they motor does not operate correctly. if you are postive the carbs are clean, and spark on both cylinders. it would not hurt to check compression. did you follow the post in the faq forum, on clean carbs.

 

[quackaddict1]

Re: 28hp woes

Compression on both cylinders is good, 115 and 120. I have done as the carb rebuild page has required, this particular carb is fairly simple, and since the low end is working it makes the rest of the breakdown even easier. The bowl is full of fuel whenever we remove the carb, but you can watch the carb run out of fuel as you rev the motor up. I will look into a link and sync.