Rejetting=Power loss?

LubeDude

LubeDude

Admiral
Joined
Oct 8, 2003
Messages
6,945
I rejetted my carbs on my 87 Merc 150 last winter when I redid the Reeds. I only went from 64 to 66 on the mains because I am right at sea level and thought it may help some. I have suffered about a 5 MPH top end loss and a few hundred RPM after doing this, could this be the reason? Engine runs great other than that. Timing and sync all all right on.
 
timmathis

timmathis

Lieutenant
Joined
Apr 24, 2005
Messages
1,295
Re: Rejetting=Power loss?

This will be a good one for Clams Canino...?
 
E

emckelvy

Commander
Joined
Jan 16, 2004
Messages
2,506
Re: Rejetting=Power loss?

If you made no other changes which would increase the airflow thru the motor, there's no reason why richer jets would make it run any better. Just richer, which is most likely the cause of your performance loss.

I installed one size larger main jets on my old 1350 and it ran great in cold, dense winter air but ran like cr*p in the summer. I went back to the correct, smaller jet size and she ran nice and crisp.

I'd put the leaner, stock main jets back in and see what you get.

IMHO...........ed
 
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