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Wot troubleshooting

D

DE:1

Member
02 40hp merc. Eng has been timed and carb adjusted. Will get up to only 3000 Rpms + no hole shot. Almost like running on 1 cyl. Need some help where to start. Thanks
 
Check for blue snapping spark from each spark plug wire. When were the plugs last changed? What color are they?
 
Is it running rough? I would start with your fuel. Take a sample of it and check to make sure it's clear, fresh, and free of any water or debris. Most of the time, these kind of problems are fuel/carb related.
 
Does the bulb on the hose go hard when you pump fuel into the carburetor ???------------If it does not you may have a ruptured diaphragm in the fuel pump.---Some folks would rush out and buy a new pump without testing and inspection.------Myself I inspect and repair , costs just pennies for a repair kit.
 
Answer this question --------" do you have spark on both cylinders that will jump a gap of 3/8" or better " ???----" good spark " means little here.---What are the compression values ??
 
Good blue spark. Comp is 120 both cylinders.
Fast idle lever moves three inches before engine reacts. Wondering if eng linkage set up correctly also.
Looks like its going to mechanic. Because it had me stumped.
 
Provide the history / details----------Is this motor " new to you " ?----------What boat is it on ?---------Is this something that developed suddenly ?-------Slowly got worse ?--Will spark jump an actual gap of 3/8" ?
 
New to me was on 13 whaler. On a 16
lowe bass boat. Spark will jump 3/8. Just
does not want to wind up under load. DDon't
know much about eng before I got it.
 
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