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Minor loss of RPM at cruising speed

ppass1954

New member
"This problem is occuring on m

"This problem is occuring on my 97 Sea Ray 330EC with twin 7.4 Mercs (500 hours).

At cruising speed (2500-3600 RPMs) the port engine losses sync (I am guessing 25-50 RPMs I can hear the change and see it on the sync guage) for about 15 seconds and then regains the synced RPMs. This occurs very intermittently - sometimes I can run for an hour without an issue, at other times this will occur every few minutes. This problem started the beginning of last season and seems to be occurring with more frequency over time. I have replaced plugs, wires, rotor, cap, fuel filter.
Any insight is greatly appreciated."
 
"I have run the tanks almost d

"I have run the tanks almost dry, replaced the fuel filters and refilled the tanks and it didn't help."
 
"Check for a vacuum leak. If

"Check for a vacuum leak. If it is not visible to you, test for it when it is running poorly by using a can of WD-40. It will burn so be careful. Spray around carb or throttle base gaskets, vacuum hose connectors and the intake manifold gasket. You can also use a small canister of unlit propane on a low setting. Any leak will suck the fuel in and increase RPMs immediately. Wallah! You have found the problem."
 
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