Power loss...Help!!!

[Phildoo]

Was tubing yesterday and shut down the engines to leave lake, starboard engine ran great then started to kinda backfire and pop, not getting full rpms now. Brought home and tried it and sounds fine out of the water, so ran back to lake to load test it and same thing..
Gonna start looking at stuff so if anyone has general ideas please let me know!!

 

[Dr Honda]

if you got a true "Back fire"... then you could have ruptured the diaphragm in the carb. It's not a common thing... but it can happen.

Either way... a back fire can mess up the carbs. I would start with a cleaning.

 

[Phildoo]

Its weird, it "popped" a couple times but hasnt since??..just no power under load now.
Pulled plugs and seemed oily and black

 

[voodoo]

Check the RAVE valves for sticking and once they are out you can hear the hissing sound if the diaphrams are OK, next place would be the muffler gizmo that looks like a RAVE valve top, same idea - hissing sound.

 

[Phildoo]

New plugs=problem fixed. Strange.
Back to new under load. 2 strokes are so sensitive!!
I had just cleaned the raves about 2 weeks ago but havnt done the ones on the mufflers yet. Think I will.

Another quick question. I rebuilt the carbs on one engine and now get a super high rev out of the water (way high). What needs to be adjusted that I missed?

 

[voodoo]

2strokes are lots of power for the weight, they must have fuel and oil or quickly burn out, if you can rev up now with one fix the other one, should be 3000 on land but most important 1500 in water - adjust accordingly, use a balance vacuum guage to get in sync, hard to beleive plugs fix this - make sure your paddles and flags are good.

 

[Phildoo]

I know, I was hesitant also, but dropped ass end in the water and have my power back..plugs were very oily though. And probably not even 15 hours on them either. So I adjusted the lsa to 1 1/2 out. Seemed to be pretty close to where it was before. Guess its better to have to much oil than not enough.

 

[daverade]

just an idea...i tightened my throttle cable just a tad too much on my ski on the adlustment at the carb, and when i started it, it was cool barely touched the throttle it jumped to like 5000 then would only go down to like 3000...in the water it just couldent retract all the way....quick adjustment all was well