Turning over a Mercruiser 5.0L

[dmgiraitis]

My engine would not turn over last time I tried to use my boat and I want to use a 1/2 drive ratchet and bar to manually check to see if the engine is not seized or binding. Anyone know the size socket for the nut on the front of the crankshaft pully? My boat is a 2 hour R/T from the nearest tool store and you will save me several hours if you can provide this information so I can get the right socket on the way out there this weekend. Fortunately, I have access on the front of the block. Thanks

 

[crazy charlie]

Re: Turning over a Mercruiser 5.0L

I would highly recommend pulling the plugs before you try to crank or move it by wrench.This will allow the motor to crank easily and help isolate the problem.You may want to bring a freshly charged battery with you as well and make certain your shifter is in neutral.Charlie

 

[rbezdon]

Re: Turning over a Mercruiser 5.0L

Charlie has good advice. The most common reason for an engine to lock is hydro locking. Pull all the plugs and then check if it turns. By the way, my Chevy 350 has a 5/8 head on the harmonic balancer bolt but if thats the only tools youre bringin, you are not going to get very far toward getin that ole boat up and runnin!! I would bring a complete set of sockets and extensions both 3/8 and 1/2 drive, screw drives, plyers of all tytpes timing light compression tester, all the things you have seen here posted in the 100s of postings on similar topics to your situation. It would be a complete wate of time to drive all the way up there with the socket to fit the Harmonic blot just to see if you can turn over the engine. And as Charlie says, bring a good fresh battery alond with a DVM to test all of the electrical connections. Just as likely to have an electrical problem making it look like the engine is locked as it is for the engine to actually be locked!!

 

[Bt Doctur]

Re: Turning over a Mercruiser 5.0L

Or the drive itself may be locked up.

 

[codfather II]

Re: Turning over a Mercruiser 5.0L

Take all the advise in above postings! I had a new engine hydro lock myself. I could hear the starter clicking hard with no turn of the engine whatsoever. Pull the plugs first and try from there. By the way, what kind of engine do you have?

 

[Bondo]

Re: Turning over a Mercruiser 5.0L

Ayuh,............<br /><br />Without pulling All the Plugs,......<br /><br />You stand a Very Good Chance of Stripping the threads out of the Crankshaft...............

 

[dmgiraitis]

Re: Turning over a Mercruiser 5.0L

Thanks for all the good advice. I have a complete set of 3/8 drive sockets but not of 1/2 drive. However, I will pull as many plugs as I can (access to plugs is terrible) before I attempt to turn it over. It ran fine when I put it to bed last month and it was placed in a storage cradle, so hopefully there is no water in there. If I get lucky, it will be a bad ground or a loose lead to the starter. The quick response on this site surprised me, so I will have to visit here often. Thanks to you, I might be able to keep this old Chris Craft running.

 

[Don S]

Re: Turning over a Mercruiser 5.0L

To take a different dirction on your problem. Is it not turning over because the engine is not trying to crank? Any clicking , or just nothing at all. Makes a big difference. Especially if you go there looking for water to find it all dry and the engine turns with a socket and breaker bar.<br />Is it a bad starter, ignition switch, wiring?????<br /><br />Try this also while you are there.<br /><br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=24;t=012808;p=1#000000

 

[Bondo]

Re: Turning over a Mercruiser 5.0L

I will pull as many plugs as I can (access to plugs is terrible) before I attempt to turn it over.

If your motor is hydro-locked,.........This Isn't Good Enough............<br /><br />Reguardless of How Hard it is to get to the Plugs,.........They ALL have to come Out.......