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Tan
Tan, MerCruiser Certified Technician
Category: Boat
Satisfied Customers: 11079
Experience:  40 yrs. experience with complete engine repairs both inboard/outboard and MerCruiser Certified Technician.
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Tan this is the guy with the 75 hp 2 stroke 4cel merc 1985

Customer Question

Tan this is steve the guy with the 75 hp 2 stroke 4cel merc 1985 replaced all coils new brain box wires plugs all cel.fire great when put in water shuters pops wants to go but no the 2 plugs were black bag but got good fire gas is good
Submitted: 5 months ago.
Category: Boat
Expert:  Tan replied 5 months ago.

Hi Steve. Popping could be misfire from crossed wires or lean fuel condition carburetion. Choke the engine when it acts up. Does it run better? Try squeezing the primer bulb when engine acts up. Does engine run better?

Customer: replied 5 months ago.
A little the thred plug is black all others are firing good but i check spark amd it is firing great what do you think about the read valves why would one cel be ok and other one be. Bad same carb I dont know
Expert:  Tan replied 5 months ago.

What is the compression on that cylinder? If you have a bad reed the carb will spit fuel out the front of the carb. Does it spit fuel on the carb for that cylinder?

Customer: replied 5 months ago.
No
Expert:  Tan replied 5 months ago.

Did you try the choke and squeezing the primer bulb when engine is acting up? Does it run better?

Customer: replied 5 months ago.
Comp 100 lb
Expert:  Tan replied 5 months ago.

Did you try the choke and squeezing the primer bulb when engine is acting up? Does it run better?

Customer: replied 5 months ago.
The manual choke i pull it up it dies i never have had it start with out starter fluid and the elect choke is disconted i better fix that first.i thought. I got a deal on this boat. You get what you pay for dam well im going fishing and work on boat tomorrow it driving me nuts.i wish i had money to put in shop let them fix oh well thanks .
Expert:  Tan replied 5 months ago.

With engine running pull each plug wire off does the engine loose rpms? Use insulated pliers on the plug wire.

Keep me posted.