5.0 liter Mercruiser slow starting

[gjohnson1969]

Hey guys,
I'm new to the forum as I just purchased my first boat. It's a 1999 Glastron GS205 with a 5.0 liter Mercruiser. The motor runs great, only has 100 hours on it, however, It's giving me a little problem with starting. It just seems to drag like the battery is low. I've put two brand new batteries in it and it still did the same thing. I noticed the battery cables were pretty rusty so I replaced those and cleaned up all the remaining terminals to the starter and the grounds. It's starting a little better but still doesn't start as quickly as I thing it should. It tends to hesitate for a moment when you turn the ignition switch all the way over and then starts turning over somewhat slowly but then speeds up and cranks. Could the starter be bad? Or does the starter just need to be removed and the brushes cleaned? Any information to help fix this would be greatly appreciated.

Gjohnson

 

[95yj]

Re: 5.0 liter Mercruiser slow starting

If it's cranking slow, and your connections are good and your battery is good, then it could be your starter or it could be that you're getting water in the cylinders and getting a bit of hydrolocking. Especially since it cranks slow and then starts to speed up.

 

[gjohnson1969]

Re: 5.0 liter Mercruiser slow starting

I don't think it's hydrolocking as I ran it for over two hours straight at the lake this past weekend and it ran like a top. Motor is smooth as silk once it's cranked and running. I would think if I had run it with water in the cylinders that I'd have bent some rods and would be hearing some real bad sounds in the engine.

Any other ideas?

 

[milkyway]

Re: 5.0 liter Mercruiser slow starting

Is it carburetor with some thunderbolt ignition?

Describe in detail how you to start it. Do you pump the throttle?

 

[95yj]

Re: 5.0 liter Mercruiser slow starting

Water in the cylinders is just an idea to eliminate. If a little is leaking in through the exhaust, you'll get extra compression and then it will blow out the exhaust and will crank faster. A lot will bend rods or ruin the pistons as you stated. While the motor is running, a little water flow will just be eliminated. Besides, if it's coming through a bad exhaust manifold, it usually only comes in when the motor is shut down. Just trying to eliminate possibilities.

If you're sure that your connections and battery are good and the battery has enough cca and there's no water in the cylinders, pull the starter and have it tested. Only other thing that will cause slow cranking is if the timing is advanced too much and the ignition is fighting the starter.