5.0 starting

[mjgates]

I have a 5.0 Mercruiser, and it doesn't start as easily as the 3.0 I had in my last boat. Not overly difficult to start, but have to pump the throttle a time or 2 and let it crank for about 10-15 seconds. Sometimes takes a couple tries. The 3.0 I had was like cranking a car. Turned the key and it cut on.

Other issue I have it once I am out and the engine is warmed up, then I go to crank it and it won't crank. I let it sit for a little but, then I can crank it again.

Any ideas on what to check for these issues.

Thanks

 

[Don S]

Re: 5.0 starting

When was the last time the engine had a full tuneup, carb adjust, timing check etc.?
Does your 5.0 have a year, or better yet a Merc SN? things do change from year to year believe it or not.
When you say "it won't crank", does that mean the starter won't turn the engine over, or the engine doesn't start?

 

[mjgates]

Re: 5.0 starting

I just bought it at the start of last season, so not sure when the last tune up was. I replaced the plugs last year, and had it looked at and water tested by a marine Surveyor before buying. The engine is a 1999. The engine is turning over, just not starting as the old one I had. I would like it to ideally fire just as a car engine would, or close to it. I've changed the plugs, getting a new battery this season, which should take care of any voltage or spark issues. So I'm thinking something with the carb or fuel supply. Not sure how to adjust the carb, or what else is involved with a regular tune up.

 

[Don S]

Re: 5.0 starting

A tuneup consists, of spark plugs (NOT champions), cap, and rotor, doing a compression test. Then checking the idle timing, and adjusting the carbs idle mixture and idle rpm (while in base timing mode). You may also need to make sure the choke is adjusted correctly, the flame arrestor is clean. Also verify all the plug wires are in good shape and the ends are not corroded where they go into the cap and on the plugs.

Oh, and follow the manual.
If you don't have one, download it here http://www.4shared.com/document/Pss92fbC/Service_Manual_24.html

 

[mjgates]

Re: 5.0 starting

Thanks Don. I think I'm going to take it in and have it professionally done. It's $95 plus parts, so shouldn't be too bad and I know it will be done right. One of these days I'll get to the point I can start doing everything myself.