Help!!! 5.7 350 OMC wont start or crank

[cmayer85]

I just bought a used complete 5.7 OMC motor for my boat. I pulled my omc stringer intermediate and put it on the new motor and everything bolted over fine. (had a 3.8 OMC previously) i put the engine on a pallet and tried to start it but nothing happens. if i pull the spark plugs and send 12v to the starter it will turn the crank slowly. when i put them back in nothing. its like the starter doesnt have enough power to turn it, or it gets jammed. another issue is that i was not getting any spark at all. could this be caused by the motor not cranking or not cranking fast enough? i dont have much experience with small blocks and carbs. any and all help is very very appreciated. i am just trying to get this boat on the water in the next month or so.

 

[mkast]

Re: Help!!! 5.7 350 OMC wont start or crank

Sounds like:
1. Low battery
2. Poor electrical connections, cable too small for load, poor contact

 

[drrm123]

Re: Help!!! 5.7 350 OMC wont start or crank

put a breaker bar on crank bolt and see how hard it is to turn over by hand with plugs removed. if hard it could have rust on cylinder walls if not maybe a bad starter, you can take to local automotive store to have checked.

 

[cmayer85]

Re: Help!!! 5.7 350 OMC wont start or crank

i dont think its a battery issue? i had it connected to the battery and a charger on the battery at the time. and i pulled the starter and it works fine when tested off of the motor. the cylinder walls shouldnt be an issue either. it cranks over ok when i put a ratchet and socket on there.

 

[a70eliminator]

Re: Help!!! 5.7 350 OMC wont start or crank

You already have some good advise, sounds to me like as already suggested have that starter load tested at the autoparts store, it's pulling too many amps and thats a common failure with starters.

 

[Gary H NC]

Re: Help!!! 5.7 350 OMC wont start or crank

A bad starter can still spin fine on the bench...have it tested then go from there...Most auto parts stores will test for free...

 

[bruceb58]

Re: Help!!! 5.7 350 OMC wont start or crank

You don't know the history of the starter. Who knows if has been dunked in water and is a rusty mess inside. It can look fine on the outside but look horrible inside.

 

[cmayer85]

Re: Help!!! 5.7 350 OMC wont start or crank

do you know what kind of automotive starter i can use on this? nobody here has omc parts so i pretty much have to order it an wait a week or find one that will work from a car/truck from the mid 80s. i just went to autozone and all of the car/truck starters look exactly the same except where it mounts to the block. the pic below is my starter and you can see the two mounting holes. all of the car/truck starters i looked at had the lower one moved to the left about 1.5-2". are the marine starters different or can i find a car/truck starter.

http://i572.photobucket.com/albums/ss165/cmayer85/Photo0117.jpg

 

[Lodgepole]

Re: Help!!! 5.7 350 OMC wont start or crank

Man, that is one sad looking starter! If it was mine, for a start, I would open it up and check for internal corrosion of the contacts where the solenoid pulls the contacts to kick the starter in. From the looks of the outside, these contacts may be not carrying enough amps to turn the engine over. Also check out the comutator, brushes and bearings. You should be able to get parts to fix this stuf at the parts house. If the solenoid contacts are bad, then it will sure test bad. Could also gave corrosion onside the solenoid causing the plunger to drag. If nothing is obvious, then a parts house test will tell.

 

[cooter2506]

Re: Help!!! 5.7 350 OMC wont start or crank

That starter looks like it has seen water. Also, someone correct me if im wrong but, dont put automotive starter in there. It might make for a huge mess of boat parts on the lake when it goes BOOM!!

 

[CheapboatKev]

Re: Help!!! 5.7 350 OMC wont start or crank

That starter looks like it has seen water. Also, someone correct me if im wrong but, dont put automotive starter in there. It might make for a huge mess of boat parts on the lake when it goes BOOM!!

Cooter your right..Out on the lake, using in an actual boating enviroment, yes, never ever use an automotive starter/alternator,carb...never..
HOWEVER he has this engine pulled and on a pallet...not in a doghouse with fumes, for testing ONLY...maybe auto just for this testing..I personally would take that starter to any competent elect shop and have her rebuilt, to marine specs

 

[meesh]

Re: Help!!! 5.7 350 OMC wont start or crank

What kind of cables are running to your motor? Jumper cables will give you a poor connection. You need to make sure those cables are bolted to your block neg side and to your starter pos side. Poor connections will lead you start fixing the wrong things. Also as stated above , automotive stater is fine for a pallet but make sure you have a marine stater when it goes in the boat.

 

[cmayer85]

Re: Help!!! 5.7 350 OMC wont start or crank

the cables are not jumper cables, they are the cables that go on the motor when in the boat. i will take the starter apart and look at it. it is just really dirty right now. what is the difference between the marine starters and the auto starters, i am new to this

 

[CheapboatKev]

Re: Help!!! 5.7 350 OMC wont start or crank

the cables are not jumper cables, they are the cables that go on the motor when in the boat. i will take the starter apart and look at it. it is just really dirty right now. what is the difference between the marine starters and the auto starters, i am new to this

Go to the top of this page and under SEARCH FORUMS, type marine versus auto parts, or just auto parts....you'll see lots of past threads on this subject.
In a nutshell..Marine parts are spark sheilded to protect you from any explosion from gas fumes or vapors which accumalate under your engine cover, below deck, ectera..the fumes are wht boats have blowers to suck air away from this area before you start her up...

Welcome Aboard...

p.s.
Do us a favor and resize that 500 lb starter pic..it is huge! lol

 

[cmayer85]

Re: Help!!! 5.7 350 OMC wont start or crank

haha sorry about the pic size. i am having the starter rebuilt today. they said it would only be $45!

 

[mark1905]

Re: Help!!! 5.7 350 OMC wont start or crank

haha sorry about the pic size. i am having the starter rebuilt today. they said it would only be $45!

Brand new marine starter for $60:

http://www.db-starter-alternator.com/Starter Motors/Marine/Inboard/

 

[cmayer85]

Re: Help!!! 5.7 350 OMC wont start or crank

so the guys at the starter shop said its not the starter. he tested it for a while and it spun fine.

 

[Howard Sterndrive]

Re: Help!!! 5.7 350 OMC wont start or crank

so the guys at the starter shop said its not the starter. he tested it for a while and it spun fine.

1. You coulda done that
2. That says nothing about the starter's condition
3. Shouldn't spin a starter for more than a few seconds without load. Can damage it.


I like the advice above about trying to bar the engine over. The engine could be tight.
Did the intermediate shaft turn freely before you bolted it to the engine?

The "no spark" issue is not related to cranking rpm. Spark is as strong at 5 rpm as it is at 250 rpm.
However, if a tight engine is drawing the battery down due to high starter current draw, that could cause no spark.

 

[CheapboatKev]

Re: Help!!! 5.7 350 OMC wont start or crank

I just bought a used complete 5.7 OMC motor for my boat. I pulled my omc stringer intermediate and put it on the new motor and everything bolted over fine. (had a 3.8 OMC previously) i put the engine on a pallet and tried to start it but nothing happens. if i pull the spark plugs and send 12v to the starter it will turn the crank slowly. when i put them back in nothing. its like the starter doesnt have enough power to turn it, or it gets jammed. another issue is that i was not getting any spark at all. could this be caused by the motor not cranking or not cranking fast enough? i dont have much experience with small blocks and carbs. any and all help is very very appreciated. i am just trying to get this boat on the water in the next month or so.

Just re read your orignal post...
1. did you see hear smell (kidding) this motor actually RUN before you purchased it?


2. Have you tried spraying PB blaster down the cylinders (lots of it) before trying to turn her over with the plugs out?


3. Forget about the spark issue for the time being..one at a time, slow and steady


4. battery fully charged, GOOD clean connections? Wire brushed and spotless?


5. Thanks for cutting that starter back down to its original 20 lbs!

 

[cmayer85]

Re: Help!!! 5.7 350 OMC wont start or crank

I dont know how long the engine sat and no i didnt hear or see it run, i guess i was a little too trusting. the guy owns a boat repair shop outside of dallas so i figured he would not lie about it. i might be wrong.

I did not spray pb blaster or anything down the cylinders or prelube, i will try that.

The guy that checked the starter put it on his test bench, i guess i cant rule it out just yet.

I will double/triple check the battery and connections and make sure everything is good.