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1970 Evinrude 9.5 HP Need help with elevation change

S

Slimbob

Member
Hello,
A friend of mine has a MD# 9022A, SN E11586. He believes it is a 1974 or so.

Problem is he is in Phoenix, AZ and the engine runs fine.

When they head to the mountains (~6500 ft) it is very hard to start and runs poorly.

I thought this is just a air/fuel mixture adjustment.

He claims that they tried that to no avail.

Does he have to change out a jet to support the thinner air?

Or should an adjustment correct for altitude.

Don't have a manual yet.

Thanks for your help,
Slimbob
 
kimcrwbr1,
Thanks for your quick reply. Would that be #75 on parts breakdown you sent the link for?

If so, looks like it is available externally. Don't need dis-assembly? Is that right? This guy is not a tool wizzard.

Thank you,
Slimbob
 
The last year for the 9.5 was 73, then it was discontinued and the 9.9 came out......same as the 15. The adjustment is only the low speed. The older 10's had a separate high speed adjustment and had a bit more "snap". The latter would be my choice for major altitude changes. As Kim says, you will loose power but the 10 hp will almost make up for it, they had higher compression ratio.
 
Thanks again guys!
So the hard starting at altitude is probably an adjustment on the low speed air/fuel mixture and idle screws.
But the poor performance at altitude is probably due to wrong High speed jet installed also. Possibly too deep pitch prop also.

Hope I have this correct.
Slimbob
 
Right, I think a 6 hp prop will fit the 9.5 also and provide a bit more rpm. It may be a weak spark too, make sure it can jump a gap near 3/8" with a good fast pull, plugs out. It will also run better with more air under the cowling. I drill several 3/8" holes in the lower cowling under the front of the carb in these motors, they have a shortage of air to begin with. Have him check how it runs up there with the cowling off as a test.
 
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