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Charles, Marine Mechanic
Category: Boat
Satisfied Customers: 3929
Experience:  US Navy (Ret) Certified Mercury Marine Tech with over a decade of repair experience.
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I have a boat with a 2003 Mercruiser 6.2L MPI. It has gotten

Customer Question

I have a boat with a 2003 Mercruiser 6.2L MPI. It has gotten progressively harder to start after sitting all week, a few months ago it just took 2-3 times to get it started, then I had to put the throttle all the way down (assumed it was flooded) to get
it started, now won't start at all. Took off the plugs and they were fouled, replaced plugs and starts OK now (still a little hard to start). When it was starting it would start OK after that first initial hard start for the rest of the weekend. Fuel pressure
holds steady for 30+ minutes when I tested it. Not sure what it could be?
Submitted: 2 years ago.
Category: Boat
Expert:  Charles replied 2 years ago.
Check to make sure that the IAC is not sticking on the engine. This is what allows the extra air into the intake for idle and start up. If you have a scanner, you can watch the function of it while the engine is running.
Customer: replied 2 years ago.
The IAC is functioning normally, I was able to check that last night.
Expert:  Charles replied 2 years ago.
What is the fuel pressure holding at?Does the air intake sound different when the engine is running?
Customer: replied 2 years ago.
Air intake sounds normal. Fuel pressure was around 30psi.
Expert:  Charles replied 2 years ago.
How does the air breather look? Would the engine start easier with it off?
Customer: replied 2 years ago.
I tried with the breather off, still had the same issue with starting.
Expert:  Charles replied 2 years ago.
Are the plugs still getting fouled when you are trying to start the engine?
Customer: replied 2 years ago.
Yeah, I put new plugs in and it got it started (although still was a challenge). Took the plugs out after 2 runs and they look rough again.
Expert:  Charles replied 2 years ago.
How did you check the IAC?