Outboard Losing Power

[fisho_83]

Hi All,

Yesterday whilst on my way back to the ramp, my 2 stroke 40HP Merc suddenly lost some power and was probably only running at about 60% power. I was able to rev the engine enough just to get the boat on the plane. Checked the fuel filter, it was brand new fuel, spark plugs were pretty new as well, oil/fuel ratio was also correct. Turned the motor off, started fine, idled beautifully, but would just not rev highly. Eventually, I opened the choke all the way out whilst the boat was running and then pushed the choke all the way back in and the engine roared back to full revs and was working beautifully after that. It continued to run well for the next 30 mins. I guess my question is what would cause this loss in power? Is it possible, that the choke was accidentally opened up and I was driving along with the choke lever out a bit, or could there have been some gunk in the jets and when I opened the choke it just pushed this gunk straight through??? Just trying to figure out if there is any need to stress about this problem, or was it just a minor drama that has now resolved itself!!

Thanks Guys

[kennzo]

I think your on the money with the partially closed choke. Two strokes will generally bog out quickly when choke is applied whilst running but a slight close would be enough to restrict air and overfuel at higher rpm demands. If the issues resurfaces might be worth a carb tear down and clean.

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[Spaniard_King]

Be care full !!! a 2 stroke will make really good power/heat if run lean from a partial blockage in a carby... this will last for a short while and can end up with some melted internal parts etc

It certainly sounds like a fuel blockage of some sort!