Starter spinning but intermittently turning engine

[Josephmast94]

1992 mercruiser 5.7 350. When I turn the key I can hear the starter running, almost a slight grind but mostly just sounds like it's free spinning. The engine will VERY slowly turn over then stop for a second or 2 then turn slowly again. Mabe a 1/4 turn at the pullys after 5 seconds. Battery is brand new and fully charged. I pulled the starter last night and the flywheel looks fine and the gear that engages it looks fine. There are 2 shims between the starter and the block that were there when I bought the boat. Any ideas?

 

[achris]

Slipping clutch in the Bendix... Have an auto sparkie look at it...

Chris...

 

[Josephmast94]

Slipping clutch in the Bendix... Have an auto sparkie look at it...

Chris...

So I need to replace the Bendix?

 

[Scott Danforth]

you may need to replace the bendix
you may need a replace the contactor
you may need to replace the starter
you may only need to clean your battery cable connections

the shims are common when installing a starter (part of the installation is to measure pinion backlash)

I would take your starter to a starter/alternator shop. it may only cost you about $30 to be back on your way.

cleaning all your battery cable connections at the battery, slave contactor, starter, block ground, battery switch, etc costs you nothing. by clean, I mean shiny and clean enough your wife and children can eat off them.

 

[silver_power]

Check battery, cables, solenoids, starter and block ground. If these are ok (shinny connections etc) and the motor still does not spinning fast, pull out the spark plugs to check for water inside the cylinders. But for sure you must go for a professional bench test of the starter.

 

[Josephmast94]

10-4. thanks guys. I will clean everything up this evening and if that doesn't work I'll pull it again and have it checked out at a shop tomorrow.

 

[CamaroMan]

rarely seen shims needed for starter to engage, a light grind might indicate over shimming - try with the shims out and see.. usually shimming moves the starter away - the kits come with the shims in case and maybe the previous installer thought they were something special-

The starter spinning is also sometimes indication of the starter solenoid not kicking the gear out far enought (sticky old grease)..

I would def try without the shims first-

 

[Scott Danforth]

rarely seen shims needed for starter to engage, a light grind might indicate over shimming - try with the shims out and see.. usually shimming moves the starter away - the kits come with the shims in case and maybe the previous installer thought they were something special-

The starter spinning is also sometimes indication of the starter solenoid not kicking the gear out far enought (sticky old grease)..

I would def try without the shims first-

opposite

if you are grinding, you need to add shims. the starter bendix is below the CL of the crank, adding shims increases the distance to increase pinion to ring gear backlash.

 

[Tassie 1]

As well as the great advice in the above posts re the starter motor,
while waiting for it to be repaired put a socket/ ratchet on the pulley and check that the motor turns over and you don't have a bigger problem

It is most likely just the starter motor though

 

[Scott Danforth]

Never attempt to turn over a GM motor from the crank bolt. it will break off the bolt or strip the threads

either use a bar with two fingers to go thru the balancer holes, or use a crank socket.

 

[Tassie 1]

Never attempt to turn over a GM motor from the crank bolt. it will break off the bolt or strip the threads

either use a bar with two fingers to go thru the balancer holes, or use a crank socket.

Thanks for posting the proper method and why,

wasn't aware of that,

 

[Bt Doctur]

The unlucky one`s have found out why you don`t do something like that,

 

[Grub54891]

The unlucky one`s have found out why you don`t do something like that,

I admit nothing. But hey, I was 14.

 

[Tassie 1]

The unlucky one`s have found out why you don`t do something like that,

How do you turn the motor over otherwise to check for a seized motor, which is what l was implying but not saying, in my first reply?

had much the same symptons yrs ago
starter would turn the motor a fraction

Two marine mechanics had put a socket/ ratchet on the pulley nut,
only to see if it would turn over further than the above
it didn't

 

[Scott Danforth]

a large strap wrench on the bottom pulley

pull the bolts on the bottom pulley, then install longer ones to pry with

custom made up bar with a few tines to turn the damper

screw driver to rotate motor by flywheel ring gear teeth

pull damper and use a crank socket.

first time I messed up a SBC crank was when I was 13.

now a buick crank has a much larger bolt and you can get away with it.

 

[Tassie 1]

My apologies to the op for hi jacking your post,

what was available at the time was used on my moored boat more than a 130k's from a marine workshop
it took less than 15 secs.

it showed the motor was seized,

Nothing got broken, no knuckles were scrapped,
Though l did get a bit teary to be brutally honest

now, back to the op's problem...

 

[Josephmast94]

I think I found the issue last night (see pic). Not sure what made it do this but the 3 ears sheared off and apparently the ring gear was just spinning inside the housing instead of spining the flywheel. I just picked up the new part so hopefully I will be able to get it installed and tested tonight.

 

[Bt Doctur]

That would cause a problem but the question is what caused it to happen.I would pull the sparkplugs if the motor dosent respond immediatly. Those starters dont take kindly to a hydro-lock condition and will rip the plastic planetary gear right out.
To check a motor to see if it is seized or difficult to turn over:
1 Remove the drive and insert a T handel with a old shaft welded to it.
2 Remove the front pully bolts , and nose bolt. .install 3 longer bolts and place the prybar between 2 of the bolts

 

[dlogvine]

I would start with checking the starter first, since you took it out anyways. It might be as simple as the solenoid not kicking out completely. And solenoid problem could be easily fixed by replacing a bad solenoid with the marine one bought for around $15-20. If the starter is good, which any autostore can check for free, turning the engine could be made easy by removing the spark plugs and just using a prybar on the crankshaft pulley main bolt. The engine should turn without much effort.

 

[dlogvine]

How do you turn the motor over otherwise to check for a seized motor, which is what l was implying but not saying, in my first reply?

had much the same symptons yrs ago
starter would turn the motor a fraction

Two marine mechanics had put a socket/ ratchet on the pulley nut,
only to see if it would turn over further than the above
it didn't

If the engine was not turning or turning with a lot of force applied with removed spark plugs, they should not have used the crankshaft bolt with the socket and an extension wrench, this could have stripped the bolt and damage the crankshaft, an expensive repair.