'85 50HP 2-Stroke - runs poor with wrap-around cowl on

[joewg3]

Hi All - Finally (with your help) seem to have my motor running like a beast, but only with the wrap-around cowling off. I'm running 5500RPM at WOT with it off, 4000RPM WOT with it on. Pretty obvious there's an air issue. Is it possible there is an exhaust leak causing dirty air? I've read that the base gasket between the powerhead can cause this. Also read that sometimes there may be an electrical short caused by the cowl. Anything else to check out?

 

[racerone]

Spray some extra oil into carburetors while running.----Should make it easier to find exhaust leakage.-----My bet is on plug wires or sparkplug boots as the issue.----Replacing plug boots is what I would do first.

 

[Faztbullet]

Check for leakage around top motor mounts

 

[BWR1953]

Hi All - Finally (with your help) seem to have my motor running like a beast, but only with the wrap-around cowling off. I'm running 5500RPM at WOT with it off, 4000RPM WOT with it on. Pretty obvious there's an air issue. Is it possible there is an exhaust leak causing dirty air? I've read that the base gasket between the powerhead can cause this. Also read that sometimes there may be an electrical short caused by the cowl. Anything else to check out?

I had the same problem. This is what I did.

 

[joewg3]

I had the same problem. This is what I did.

NICE. Looks like a good fix until winter!

 

[racerone]

You can see the smoke and exhaust leaking in the first video.----That would have been the clue to find the exhaust leak.

 

[joewg3]

I went out again and figured it out. Definitely a plug wire. Putting the cowling on just the back a little made it cut out, so it couldn't be an air/exhaust issue. I pushed a plug wire and got zapped big time!

Thanks for all the help guys. Really appreciate it.

 

[jimmbo]

I had the same problem. This is what I did.

A bit of EGR happening there...

 

[BWR1953]

I went out again and figured it out. Definitely a plug wire. Putting the cowling on just the back a little made it cut out, so it couldn't be an air/exhaust issue. I pushed a plug wire and got zapped big time!

Thanks for all the help guys. Really appreciate it.

Cool!