2000 Mercury 200hp saltwater (carburated) surging/throttle probs

blkntz74

Recruit
Joined
Mar 22, 2008
Messages
3
Figured I should just open a new thread instead of hijacking foresters.

My (and his) issue is surging while on throttle. It is fine until I hit ~4500 rpm and which point the port motor drops revs to about 3500 and then picks back up. It'll keep doing this until I back down to 4000 rpm and which point it'll cruise all day. I did the filters/separators with no effect. If the fuel line is cracked or has a hole, wouldn't there be an obvious fuel leak? Also, my primer bulbs are never full except right after I prime them. The starboard motor will hit 5500 rpm without problem (It's primer bulb is also frequently soft but not to the degree of the port motors).
Another issue is with the same motor throttle cable. If I floor it, it'll hold the rpms for a bit befre the surging starts, but if I let go of the throttle, it'll pull back on its own. It only stays put at up to ~3700 rpm. Anything higher and I have to hold it in place to maintain those revs.
Thanks for any input!
-Scott
 

gss036

Commander
Joined
Jan 18, 2003
Messages
2,914
Re: 2000 Mercury 200hp saltwater (carburated) surging/throttle probs

Rebuild the fuel pump, sounds like the pump can't keep up w/demand indicating maybe a pin hole in the dipharm. And no, a vaccum leak may not show in the fuel line. Are both engines running from the same filter?
 
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