Mercruiser 4.3 starter issue

[greigph]

Morning all, I have recently done a fair bit of work to my engine and am now having starter issues I just can't get my head around.
The engine tries to turn over then the starter just spins. I can turn the engine over by hand. It's a new starter,I've removed and refitted several times but still the same issue.

Anyone have any magical wisdom before I lose the remainder of the hair I have

 

[Chris1956]

This should be posted in the MerCruiser forum.

My '88 4.3LX starter was typical for GM starters of the time. The starter solenoid would magnetically pull a piston down a cylinder, and a pivot would push the starter gear into the flywheel. When the piston met the bottom of the cylinder, an electrical contact would send electricity to the starter motor causing it to turn. The starter would not spin until the gear was engaged. You might look to see if you have this kind of starter, and why the gear doesn't engage.

 

[alldodge]

You turned it over a little by hand so doubt it's the flywheel teeth. It has to be the starter. Try bench testing it and see if the gear moves all the way out

 

[Bt Doctur]

when it stops ,what happens if the turn the flywheel 2 inches? If it now catches and stops again you have damaged teeth on the ring gear

 

[greigph]

when it stops ,what happens if the turn the flywheel 2 inches? If it now catches and stops again you have damaged teeth on the ring gear

Flywheel looks decent it looks and sounds likes the pinion catches for a brief second then just free spins. Like the starter is out of alignment.

 

[alldodge]

For me I didn't really hear it engage
Check to see if it is fully extending. If it is it might be the solenoid internal contacts

 

[dingbat]

A under voltage condition (bad connection), bad winding in the starter and a compromised battery will exhibit this same behavior.

 

[ESGWheel]

No magic but rather a process of elimination. Like the classic Clue game, need to figure out if its Colonel Mustard with the lead pipe or Professor Plum with the rope….

Given the motor turns over by hand, there are two basic potentials either the Starter or the Flywheel. Based on your post it sounds as if you have checked the flywheel for any missing or damaged teeth. As you many know this requires checking the entire circumstance. This only possible with the starter removed and then viewing the flywheel one section at a time by slightly rotating the motor and checking the next section. Repeat until the entire flywheel has been inspected. Mark the flywheel at the start to know you have inspected the full 360 degrees.

Based on the video you posted it does seem as if the flywheel is OK. This is based on the starter spins but the motor does not initially. And then without turning the motor by hand, at the next turn of the key, the motor does rotate but stops while the starter is still turning. So is like this:

• (1) Key to start > Starter motor spins, motor does not. (2) Key off. (3) Key to start > starter AND motor both spin but suddenly the motor stops rotating but can hear the starter motor still spinning. (4) Key off and frustration/confusion.

This leads me to believe that the starter is the issue. Specifically, the starter overrunning clutch. Said differently it seems as if your starter is engaging (the pinion gear gets pushed out to the flywheel and engages) but the overrunning clutch is intermittently failing allowing the motor to turn but then (under load) fails. Thus even with the pinion gear engaged and the starter spinning it does not turn over the motor.

Overrunning clutch? This is the device between the starter shaft that spins and the pinion gear that engages the flywheel. In AllDodge’s picture it’s the device just behind the Pinion. When the engine starts the pinion gear is still engaged with the flywheel and this device allows it to ‘run faster’ than the starter motor. Is akin to the 3/8 Inch Rachet you use on your Socket Set. It will ‘lock up’ one direction but spin in the other. Here are a couple of vids on this device link and link.

So, while you have a new starter, it does not mean that it is good. Try another starter is my suggestion.

 

[ROY WILLIAMS]

WRONG ENGINE STARTER . MAINTENANCE ENGINE STARTER OF THE NEW OR WRONG !

 

[Mc Tool]

Well my guess is that you have an inertia starter. ,starter engages as normal ....engine fires once or twice which spins pinion back down the bendix and then dies which leaves the starter still spinning but disengaged.
Does the engine fire at all , or just before starter starts spinning freely ?
Maybe?

 

[ROY WILLIAMS]

Well my guess is that you have an inertia starter. ,starter engages as normal ....engine fires once or twice which spins pinion back down the bendix and then dies which leaves the starter still spinning but disengaged.
Does the engine fire at all , or just before starter starts spinning freely ?
Maybe?

maintenance starter problem !!!!
off the starter brushes motor rusted HOLDER brushes ....sand paper ...