Spring time tune up on 4.3L I/O Glastron

[prc03sx195]

Hi folks, I have a 2003 4.3L Carb Mercruiser I/O and gathering parts for my spring tuneup. I don't have an engine manual so I am wondering what the spark plug # is I need. I would like to put in AC plugs but would need a conversion from the Mercruiser # to aftermarket #. Can someone provide these P/N's? Thanks in advance.

PS. I am also going to resolve a "runon" issue I have been having with the boat for a few years now, any ideas what might be causing that? When I turn the key off the engine continues to run (diesel).

paul

 

[Bondo]

Re: Spring time tune up on 4.3L I/O Glastron

I don't have an engine manual so I am wondering what the spark plug # is I need.

Ayuh,... The manuals are available in the Adults Only section of this forum,...
The sparkplugs have the # written right on them...

I believe there's a write up on curring a run on situation, But I don't have the link for it handy...
Generally, a Proper Tune Up is all that's needed...

 

[ENSIGN]

Re: Spring time tune up on 4.3L I/O Glastron

Also make sure you have the correct preload on the throttle cable,The throttle plates should close when shifting back to neutral

 

[prc03sx195]

Re: Spring time tune up on 4.3L I/O Glastron

Ok I found the engine service manual but what does 4.3L "MPI" engine stand for? Thanks

paul

 

[Don S]

Re: Spring time tune up on 4.3L I/O Glastron

Post your engines serial number. Merc goes by SN range and that SN is used for everything by Merc and anyone here that works on them for a living.
MPI stand for Multi Port Injection, EFI. If you have a carb, then you don't have MPI.

 

[prc03sx195]

Re: Spring time tune up on 4.3L I/O Glastron

Well my engine is a carbed version, so where is the manual for that? I can't seem to find it in the links. Thanks again.

paul

PS. Any more info on the runon repair?

 

[cr2k]

Re: Spring time tune up on 4.3L I/O Glastron

Run on is usually caused by one or more of the following:

High Idle condition

Air leak

Excess carbon in heads

Excessive engine temp.

 

[b18apwr]

Re: Spring time tune up on 4.3L I/O Glastron

Also make sure you have the correct preload on the throttle cable,The throttle plates should close when shifting back to neutral

^^This is what fixed the run on condition on my 4.3 this past year.