OUT BOARD ??

[luckycrank]

I HAVE A 25 HP 86' mecruy that when its choked ravs real high , whatr could cause this

[CAMAN]

It sounds like you have an air leak somewhere. Check the choke butterfly on the carb. It may not be closing all the way. Pulling the choke is supposed to close off most of the air intake with the choke butterfly.

[boatfixer]

I HAVE A 25 HP 86' mecruy that when its choked ravs real high , whatr could cause this

That has a mechanical primer, no butterfly and also advances the timing when you pull out the "choke". They will increase in Rpms. How much does yours?

[CAMAN]

Ah, sorry, my mistake.

[luckycrank]

IM GUESSING 4500-5000 RPMS and climing by the time I shut it off.

I had a similar 25 hp that blew up on duck opener and it never did this , we swapped out a powerhead from a used motor we bought off hsolist that had a bent prop shaft .it also kills freaquently and have to keep pumping the ball to keep it running , so im guessing it needs a fuel pump diaphram also .

I see there is and adjustment for timing advance but havent any knowledge to adjust but I am a auto technician , and can probally figure it out with a bit of guidance.