35hp conversion stalling please help

[jafitzwater]

I have a 1987 johnson 20hp that I converted to 35hp.

I purchased a 35hp carb from an '83 johnson then bored out my 20hp intake manifold. I rebuilt the 35hp carb, changed all the fuel lines gaskets, the reeds were very clean and I also placed 2 new plugs in champion brand.

The motor was running okay before the conversion not perfect but would start and idle fine and also had decent pickup.

I took a video of the engine running after the rebuild and cleaning. I also rebuilt the fuel pump and have a new bulb and lines for the tank and tank gas is fairly new at 50/1.

Anyways the video is kind of long and part way through It started to act like it was getting choppy on the idle so I tried to adjust the idle needle and it stalled.

https://www.youtube.com/watch?v=-7dKKGGqu5c&feature=youtube_gda

 

[Bosunsmate]

Re: 35hp conversion stalling please help

Seems ok, you need a test tank or to put it in the water so you can see how far out your idle screw should be.
I thought i heard it lean out there for a bit.
Any question here? I suppose that may of being it?

 

[jafitzwater]

Re: 35hp conversion stalling please help

Thanks for the reply. I will take your advice and take it up to the lake. We got the engine to rev up really well without choking out.

Can you not throttle these motors up with the carb lever? Every time I did it by just pushing the lever down it would stall out? However when I used the throttle cable it would rev up with no problem.

 

[Bosunsmate]

Re: 35hp conversion stalling please help

Itd be because the motor advances faster first by the ignition becoming more "before" top dead centre and then once that is done the carb starts opening. By opening the carb without advancing the timing you a causing it to get out of its proper advancing procedure