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mercury 90hp (1978)

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paul6763

New member
Hi, to you all firstly.
I am looking for some help on a old 90 hp straight 6 cylinder 2 stroke outboard (1978)
the problem i have is, when i try to full throttle it just bogs down so i have to lighten the throttle a bit, it will do about 5to 10 mph before it stumbles.
i can run it with the muffs or in a bucket no problem at full revs in gear. only when in sea or river it seems to chuck it under load. thought it maybe a carb problem, i have stripped and cleaned them but now sure wich jets to ajust.
Any help would be great.
thanks.
 
How long have you owned it ??-----Classic symptoms of low speed jets that are set for very smooth idle but too lean for smooth acceleration.----Try adjusting them out 1/8 turn at a time.---Note , all motors sound good on a hose.-Even when in gear it is still nuetral because the prop does not have to do anything.-------------A compression test is always a good step to take.-Followed by a check for spark on each cylinder that will jump a gap of 7/16" or more.
 
Thanx for reply racerone, i have had it a couple of years but its been standing a while now, decided to try get it going again, might sound daft but wich jets are the ones i need to ajust.
 
ok cheers thats the one i thought as its the only ones ive had out when i cleaned carbs, is there a more or less setting to start at, how many turns out ?? they are at 2 1/4 each at the mo.
 
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