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Ask Dominick Your Own Question
Dominick
Dominick, Marine Mechanic
Category: Boat
Satisfied Customers: 1009
Experience:  25 Years Experience as Mechanic, 20 Yrs Boat Yard Owner/Mechanic, Factory Certified
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It idles rough, I replaced the cap,rotor,plugs, but it still

Customer Question

It idles rough
JA: Sometimes things that you think will be really complicated end up being easy to fix. The Marine Mechanic I'm going to connect you with knows all the tricks and shortcuts. Tell me a bit more about what's going on so the Marine Mechanic can help you best.
Customer: I replaced the cap,rotor,plugs, but it still idles rough enough to die when putting in into gear. Its a 99 MerCruiser
JA: Is there anything else the Marine Mechanic should be aware of?
Customer: Not sure. Example?
Submitted: 3 months ago.
Category: Boat
Expert:  Jason replied 3 months ago.

Hello my name is ***** ***** am I speaking with?

All Mercruisers are cataloged by serial number, can I get that number so I can un it and see exaclty which engine you have.

Customer: replied 3 months ago.
I am Bob. Where is the serial number?
Expert:  Jason replied 3 months ago.

Hi Bob, It's on a metal plate riveted to the engine bock just above the starter motor. It might also be on a sticker on top of the flame arrestor. Click this link for a picture - http://ww2.justanswer.com/uploads/whitesmarine/2009-12-18_054218_MercruiserSerialNumber.jpg

Customer: replied 3 months ago.
Ok I will go get it in a few minutes
Expert:  Jason replied 3 months ago.

Okay, i'll be here.

Expert:  Jason replied 3 months ago.

Any luck?

Expert:  Jason replied 3 months ago.

If you can't find the serial, Is the engine carbureted or fuel injected?

Customer: replied 3 months ago.
I'm on my way
Customer: replied 3 months ago.
0L082228
Expert:  Jason replied 3 months ago.

Got it.

This is an EFI engine. Have you done any checking on your own yet such as checking engine compression, fuel pressure, and check to see what the timing was set to?

Customer: replied 3 months ago.
Timing is good compression is good. Fuel pressure has not been checked but it runs strong up to its limit
Expert:  Jason replied 3 months ago.

If fuel pressure is high that can cause a rough idle.

What were the compression numbers, and what does the timing read at idle? Also, on the timing, does it hold steady or does it bounce around?

Customer: replied 3 months ago.
What happened to the half hour call back? I was out there in the heat waiting for over an hour. Packed it back up
Customer: replied 3 months ago.
Timing chain is good no timing bounce. The compression was checked last season. Nothing that indicated any mechanical problems
Problem started last season
Expert:  Jason replied 3 months ago.

What do you mean by 1/2 hour call back? At 1:53 I asked you for the serial number, at 1:54 you said you will go and get it in a few minutes. You finally got me the serial at 2:43, almost an hour later. I was sitting around waiting for you, not vice versa.

Customer: replied 3 months ago.
I sent the serial number at 11:43 PT.
Expert:  Tan replied 3 months ago.

Hello. My name is Tan.

If you advance the throttle just a little bit does it idle better?

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