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View Full Version : 79 4 hp wonbt run



katfish_sam
11-17-2008, 08:27 AM
"I have a 79 4 hp that was on a Jon I bought that has never ran for any extended time since I bought it. It's getting spark, compression seems good (finger in plug hole) and it's getting fuel. Thought it was flooding (wet plug) and cleaned and rebuilt the carb but it is extreamly hard to get to fire. Fuel is fresh and tank is venting. Did get it to run for about 30 sec at one time. I'm no outboard mechanic and I grew frustrated and put it away til winter, well it's winter and I still don't know where to turn next. Anybody have any suggestions / help?"

ko4nrbs
11-21-2008, 06:38 AM
Shop around and buy a service manual for it. They are very handy for troubleshooting.

Sounds like a fuel pump to me. If it runs while you squeeze the priming bulb(on the gas tank fuel line) that is a good indication of a bad fuel pump.
Bill

katfish_sam
11-21-2008, 08:05 AM
"I have bought a Seloc manual and thought it was quite helpful with the work I have done thus far.
This motor's fule is gravity fed with an internal tank. I changed the fule line and filter, rebuilt the carb and had it on and off again several times making sure all passages were clear and the float was set up correctly. My methods of checking for spark (plug out and grounded while cranking) and compression (finger over plug hole)are crude, but I would think there ought to be enough of both to make this motor run? I have to wonderer if the spark is "hot" enough or timming is out, something like that?"