Weird problem... 35hp Rude

[ddavis90325is]

So the other day my motor was running bad. It would run full throttle for about 15 seconds then die, then run really rough again. Let it sit for a while, and it would repeat this. So i re-built the fuel pump, cleaned out the carb, and ran seafoam through it and it still does it. Well i found that if i adjust the idle knob on the carb and make it run rich, it will run better, but at start up it realy really runs rough, and when it finally settles down, it smokes a lot (obviuoly since it's running rich). Does anyone have any ideas what this could be? I've had so many people tell me so many things. Anything from crap in my fuel line, to my primer ball's check valve going bad. I re-built the carb about 2 months ago, and the primer ball is brand new. Please help me!! Thanks in advance!

 

[F_R]

Re: Weird problem... 35hp Rude

What year 35hp are we discussing here?

 

[ddavis90325is]

Re: Weird problem... 35hp Rude

a 1984. Also, got it out today, and noticed this about it. When it starts, it revs up, then misses on a rythm, like vroooom -miss, vroooom- miss. It does that for about 2 min before it finally settles down and runs fine after that, but it's still running pretty rich. This is a really confusing problem....

 

[ddavis90325is]

Re: Weird problem... 35hp Rude

Can someone please help?

 

[akwalker]

Re: Weird problem... 35hp Rude

a 1984. Also, got it out today, and noticed this about it. When it starts, it revs up, then misses on a rythm, like vroooom -miss, vroooom- miss. It does that for about 2 min before it finally settles down and runs fine after that, but it's still running pretty rich. This is a really confusing problem....

Vroooom, miss, vroooom, miss sounds like its starving for gas to me

 

[ddavis90325is]

Re: Weird problem... 35hp Rude

Yep, my thoughts too, but i'm not sure what is causing it. I've cleant he carb, re-built the fuel pump, ran seafoam through it. The primer ball is new. Any ideas on what to check next??

 

[F_R]

Re: Weird problem... 35hp Rude

vroooom -miss, vroooom- miss. I have the same motor bought brand new and it has done that since day one. In fact, most two strokes do that to some extent. But ours do it a lot. The thermostat design leaves a whole lot to be desired and it takes a long time to warm up. In fact, I don't think it ever gets warm enough to open the thermostat. I just keep punching the primer to keep it going till I can get it in gear then get it the heck away from the ramp. Once it warms up it's ok. Then adjust the slow speed mixture for best running and forget it.

The quitting at high speed is another story. That sounds like a fuel delivery problem or clogged high speed jet.

I have switched to Castrol Full Synthetic TC-W3 outboard oil. A lot less smoke and oil slick, and they claim it's Bio-Degradeable.

 

[akwalker]

Re: Weird problem... 35hp Rude

Your first post says when you adjust the idle mixture, it gets better. Does your engine have a high speed needle adjustment? If it revs up when you give it throttle, runs a bit, and then dies, I would say its lean on the top end. By opening the idle mixture, the engine is getting "extra gas" from the idle circuit instaed of the high speed circuit which is where it should get it at speed. I think you need to recheck the high speed side of the carb. Also, you said you changed the primer bulb. How about the connections on the fuel hose at the tank and the engine? Fuel filter screen clean?