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5.0 LX 1987 mercruiser starter problem

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fsamie1

Member
Have not fixed the timing problem and now have a new problem. When I turn the key, pinion engages and crank turns some from 1/8 turn to full turn and then crankshaft stops and grinding noise starts. Thought starter is bad and this time bought a merc $250 starter. Same thing. here is what I have done so far:
1, cleaned battery terminals
2. disconnected coil cable, so no firing
3. Used jumper cable thinking cables are bad
4. looked at flywheel ring gear , a small portion, when changed starter and looks good.

Thanks
 
Pull that starter and spark plugs, spin the engine by hand with a ratchet and inspect the whole flywheel.

Did you check your distributor pick up for screw post or two wires? If a pick up goes bad it will lock the engine up on timing (just like a hydro lock) and break the flywheel and or the starter.
 
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2.jpg

I cannot believe what I found. Appears starter pinion only contacts tip of the ring gear in this area. It was the same for both after market starter for $70 and Mercuries starter for $220/ There is no adjustment to move starter pinion 2-3 mm. Thinking to take the starter to machine shop to elongate the holes. any ideas?
 
what does starter pinion not sitting correctly and grinding the ring gear have to do with pulling spark plugs? Compression was good 140-165 psi. I need to find a way to move starter 2-3 mm closer toward engine so there is more tooth engagement.
 
There must be a reasonable explanation for this.


it's doubtful that the cylinder block was drilled and threaded incorrectly.
the mounting bolts locate the starter motor via the nose housing's bolt bores.
the starter motor's nose housing dictates the pinion gear's extension. (via the solenoid's lever action and armature shaft stop washer)
the flywheel's FWD and AFT position is controlled by the position of the crankshaft.
the crankshaft's flange (FWD/AFT) position is controlled by the thrust bearing surfaces via the rear main bearing.
the flywheel ring gear appears to be in the correct location.


starter motor pinion travel issue for fsamie1.jpg



The ring gear is heated (expanded), positioned onto the flywheel, then cools (shrinks to fit) to gain it's friction fit against the flywheel.
Is it possible that the ring gear has shifted in one area?
If so, I would think that the problem would occur in that one area of rotation only.


.
 
This engine has been starting for 32 years.
How could anyone believe all of a sudden the starter is in the wrong location needing to "elongate" the mounting holes..

Thats absurd!

Keep digging and find the source of the issue.

You could simply have damaged teeth on the flywheel...like when someone tried to restart the engine when it was already running??
 
This engine has been starting for 32 years. How could anyone believe all of a sudden the starter is in the wrong location needing to "elongate" the mounting holes..
That was precisely my point!

You could simply have damaged teeth on the flywheel...
Click to expand...

Look closely at these ring gear teeth.
Unless I missed something...... I see no more wear than what would be considered "normal" and functional!


View attachment 21645
 
That flywheel ring gear is just worn out.

You cannot machine a starter so in engages the worn part of the ring gear, it will bind when it gets to a non worn part of the ring gear.

Again, did you look at the distributor pick up coil?
 
We will quote you or anyone else when necessary
So, you pull the plugs to check for water. It dosent take much to wipe a bendix drive new or used
 
I fully understand that all new starters mounting holes cannot be wrong. But, cannot argue with the picture. Below is the close up of the bad area. Shimming is not the main issue since it moves pinion farther down, need
to move pinion toward ring gear. looking at chowed up area length, pinion has moved to 80 percent of the ring gear tooth. There are good area that I am not showing and it shows contact at the tip o ring gear. ​
close up.jpg
 
Bt Doctur said:
We will quote you or anyone else when necessary
So, you pull the plugs to check for water. It dosent take much to wipe a bendix drive new or used
Click to expand...

what do you mean by we will quote you or …………………………
Just before it was totally shot, engine was starting with grinding noise and running so I am sure no water in it now. Actually was running last year with one exhaust flapper valve missing and I put in new ones and found the broken one by y-pipe. One question is why the pinion only chows up certain part of the ring gear and I think that area is near compression stroke.
 
fsamie1 said:
I fully understand that all new starters mounting holes cannot be wrong. But, cannot argue with the picture. Below is the close up of the bad area. Shimming is not the main issue since it moves pinion farther down, need
to move pinion toward ring gear. looking at chowed up area length, pinion has moved to 80 percent of the ring gear tooth. There are good area that I am not showing and it shows contact at the tip o ring gear. ​
View attachment 21650
Click to expand...

Thank you for the close-up view.
Upon seeing that, I would now agree that these teeth are worn.
It's time to remove the engine, pull the flywheel and take it in for a new ring gear.
Make sure that the new gear is heated equally and evenly (on a turn-table), and is not heated red hot.
 
closeup 2.jpgThanks guys for taking time trying to find the problem.
Another close up of a decent gear shows:
1. same length of axial contact
2. about 2 mm radial contact and pinion is not jumping over and tip of the tooth is ok.
3. All pictures show ring gear have not moved.
4. Below 2 mm radial contact, there is no markings. This what the issue is. Why?

Due to this contact pattern, I think if I get a new ring gear, it will only last another 2 years. Best I can think of is to move it radially a few mm for better contact pattern. I just do not understand why I am the only one with this problem. This starter is very common or V8 engines
 
Looking at the closeups I would say that there was a issue with a hydrolock condition previously and that is what chipped some teeth and caused the weardown. I would bet if you turned the flywheel about 4 inches you would find a different set of teeth and the motor would probably start just fine.
Once you get the flywhel out its a simple job to swap ring gears. drive the old one off put the new one in an oven or use a torch to get it hot enough to just slip into place
 
fsamie1 said:
View attachment 21651Thanks guys for taking time trying to find the problem.
Another close up of a decent gear shows:
1. same length of axial contact
2. about 2 mm radial contact and pinion is not jumping over and tip of the tooth is ok.
3. All pictures show ring gear have not moved.
4. Below 2 mm radial contact, there is no markings. This what the issue is. Why?

Due to this contact pattern, I think if I get a new ring gear, it will only last another 2 years. Best I can think of is to move it radially a few mm for better contact pattern. I just do not understand why I am the only one with this problem. This starter is very common or V8 engines
Click to expand...

If you think about it, if only a portion of the flywheel is worn, there is nothing you can do to move anything to make this any better.

Basically the bad wear pattern has created an " out of round" condition.

What ever the cause at this point if the flywheel requires replacement then it should be done.
Any other "adjustments" are simply a work around from fixing the results of a possible prior issue as suggested.
 
fsamie1, are you using the correct “knurled” starter motor bolts, and are they the correct length?
The knurled portion serves as an alignment dowel.
If the bolts are too long, they will bottom out before fully clamping the nose housing to the cylinder block!



.
 
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You are not the only one with this problem. Others have replaced their ring gears and cruised on, some have either parked their boat or sold the problem to someone else. Where does the "2 year cure" factor in. Do as the "baghwan" sez and replace the worn out parts.
 
RicardoMarine said:
fsamie1, are you using the correct “knurled” starter motor bolts, and are they the correct length?
Click to expand...
RicardoMarine said:
The knurled portion serves as an alignment dowel.
If the bolts are too long, they will bottom out before fully clamping the nose housing to the cylinder block!
.​
Click to expand...
​

With both new starters, for some season, the bolt flange, for the bolt, closer to flywheel, was too close to cover and would not go all the way so I replaced that one with a round head socket head bolt same length.

What is the reason the hydraulic lock? This things started when I came back to the ramp to get ice at 2-3 mph. next start, starter cranked the engine a little bit and then came to complete stop in no time. It did it one more time and 3rd time grinding started but engine started and idled ok. I decided to quit fishing due to grinding noise and dead headed cranking twice. Thanks​
 
starter cranked the engine a little bit and then came to complete stop in no time. It did it one more time and 3rd time grinding started but engine started and idled ok.

At the first stop you had water in a cylinder or more than 1 cylinder. Trying the second time chipped some of the teeth down , 3rd time the teeth were gone but got it started. Next time you had the grinding. Almost all motors will always stop in a certain position and cranking thru a hydrolock break teeth or bendix drives

 
Thanks so much Bt Doctur. I am so sure you are right. Just wonder why it happened, I have been docking same boat same way or 30 years. Do you think way of timing or cross firing have something to do with this? Other thread I started about lack of power I figured out after all this was due to bad ignition module and wires cross firing so engine would not go over 2500 rpm while in the water.
 
i have replaced dozens of flywheels due to chipped teeth and they all had chips on about 1/2 the tooth/ in automotives, back in the day, it was not uncommon to pull a flywheel and flip the ring gear. look it up. the starter is engaging correctly. do as BT and the others said, look for water in the cylinders and check the distributor. turn the flywheel to an area where it has good teeth, reinstall the starter back in the engine and the engine should turn properly, if it grinds again, turn the crank a 1/4 turn and try to spin the engine with the flywheel again.
this is common problem with chipped teeth. i know people who keep a socket wrench anf 5/8 socket on board and have to turn the crank just a hair, and the boat starts. not recommended but when you dont have the means to pull the motor, this is what ive seen.
once you accept the fact the engine has to be pulled, then move onto why it wont fire up.
 
chs said:
as for water in the cylinders, how old are your manifolds and risers?
Click to expand...

They are original form 1987. Why does it matter? 1/2 the tooth contact is pretty good compare to about 2 mm I got, please see the pictures. Not too bad to lift the engine and change flywheel. did it once before changing the coupler.
 
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