Yamaha 5Hp 2-stroke problem with WOT

M

mateomapett

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Joined
Jul 31, 2012
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3
Hi,
I' am new here, and I need your help with my Yamaha 5 Hp, 2-stroke. Motor has poor performance, it can reach only 3600 RPM-s. I cheched reed valve and cleaned the carburator but nothing has changed, what else should I do
 
9

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
9,292
Re: Yamaha 5Hp 2-stroke problem with WOT

Make sure timing is advancing properly and is in spec

How are you measuring RPMs? could be you are not getting correct reading

Could be too much prop and overloading motor
 
M

mateomapett

Recruit
Joined
Jul 31, 2012
Messages
3
Re: Yamaha 5Hp 2-stroke problem with WOT

Hi,
I measured RPM-s with inductive digital tachometer, the engine was submerged in a water tank and in neutral. I will check timing but seems to me that timing can not be adjusted? Motor starts and run normal up to 50% of throttle but when further enhances the throttle, the engine is choking and from carburetor can be seen spraying (like fog). What if the timing is not advancing properly?
 
9

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
9,292
Re: Yamaha 5Hp 2-stroke problem with WOT

Look at your service manual and see what the specs are and how to make sure it is advancing properly.

You should not be running any motor at WOT in neutral

I do not trust those tachs to give accurate RPM readings
 
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