Mercruiser Starter Question

S

SJK

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I have a '98 Mercruiser 4.3L Alpha One that I think has a bad starter, but wanted to get input.
I'm pretty sure it isn't a bad battery as I put my truck battery (Which is fairly new) and hooked it up to the boat and this battery has more CCA than the boat battery.
Here's the weird part to me...When I go to start it, it will engage and turn the engine for about 1/4 turn and then disengage and "whirr". It will do this repeatedly when I re-turn the key. I can understand that if the starter was bad it would not engage at all and just simply "whirr", but what puzzles me is that it wants to engage and turn the motor for about 1/4 turn and then disengage and "whirr". I am more than ready to go in and replace the starter, but just want to make sure that this is indeed the problem before I go and skin some knuckles. Any thoughts???

Also, the other thing is that when the starter "engages" sometimes it sounds like a loud "thud" like it is hammering into something.

I am second owner and as far as I know, the starter has never been replaced, so it is going on ~ 16 years now. Don't know what the useful life of starters would be. The motor has ~ 450 hours on it and does undergo alot of stop and starts as the kids like to wakeboard / ski / tube, etc. Has only ever been on fresh water and always put on a lift.
 
pull the plugs to check for water and see if it spins
 
quote:
Originally posted by pdecat

pull the plugs to check for water and see if it spins

Click to expand...

Bruce, Once in a while it will actually engage long enough to turn over and it runs fine when it does. It runs like a champ.
 
Certainly could be a bad starter drive but still could be water. best to find out and check compression while you ar at it. Look at the plugs if any are very clean that is a sign of water..
 
quote:
Originally posted by pdecat

Certainly could be a bad starter drive but still could be water. best to find out and check compression while you ar at it. Look at the plugs if any are very clean that is a sign of water..

Click to expand...

Will check this next time I'm up there. Unfortunately Mariah put some of these in a place where you need to be a circus performer to get to.

If this was part of the issue, would it make sense that the starter would engage very briefly (< 1/4 turn) and then disengage? I could understand it engaging and just not lighting up...
 
quote:
Originally posted by troublemaker

It sounds like your bendix is weak

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TM -
Thanks. The starter pinion (Bendix) is what I was leaning towards as it makes the most sense. I've always received great feedback on here when I have had maintenance issues and wanted to make sure I wasn't missing something else. I'll probably be changing out the starter once it gets a bit warmer. Have a few other inputs from members that I will check also.
 
Be sure to disconnect the battery. If you have a battery switch, being sure it's OFF should be OK, but I disconnect.

MerC uses a Slave Solenoid in that metal box on the stbd manifold. It, or the ignition switch, could be letting go. Just resolve it quickly, before there's any damage to the flywheel.

our MerC has the original Permanent Magnet Gear Reduction (PMGR) starter. Now over 1300 hours. The drive stuck once. I pulled it off and got it free, but took it to a shop for servicing. Shop told me the only repair part for it was the solenoid.

You can order a new PMGR starter well under $100, maybe less.

If by any chance you have the old "Delco Remy" style starter and need to replace, DO get a PMGR. Bad enough to R&R a PMGR let alone that Delco that weighs about 3x as much.
 
You might try a set of good jumper cables right from the fully charged battery to engine ground and to the starter solenoid terminal (from the remote/slave solenoid/)to help rule out bad cable or connection's excess voltage drop.
 
quote:
Originally posted by Sandy

You might try a set of good jumper cables right from the fully charged battery to engine ground and to the starter solenoid terminal (from the remote/slave solenoid/)to help rule out bad cable or connection's excess voltage drop.

Click to expand...


Sandy, we actually did this with a heavy copper cable and still had the issue. We did some troubleshooting to check the slave solenoid as well and this all checked ok.
 
quote:
Originally posted by j-d

Be sure to disconnect the battery. If you have a battery switch, being sure it's OFF should be OK, but I disconnect.

MerC uses a Slave Solenoid in that metal box on the stbd manifold. It, or the ignition switch, could be letting go. Just resolve it quickly, before there's any damage to the flywheel.

our MerC has the original Permanent Magnet Gear Reduction (PMGR) starter. Now over 1300 hours. The drive stuck once. I pulled it off and got it free, but took it to a shop for servicing. Shop told me the only repair part for it was the solenoid.

You can order a new PMGR starter well under $100, maybe less.

If by any chance you have the old "Delco Remy" style starter and need to replace, DO get a PMGR. Bad enough to R&R a PMGR let alone that Delco that weighs about 3x as much.

Click to expand...

J-D,

We did troubleshoot/test the ignition switch and slave solenoid and both were ok. I'm not sure if I have the PGMR starter or not, the one on there looks awful heavy, though!!! It's probably from ~ 1998 or so. So the PGMR starter will replace what I have if it is non=PGMR?? What year is your MerC?
 
OK! The possibilities are...

1) the solenoid isn't kicking the bendix gear out all the way. It's probably a slightly bent lever system...depending on what type you have. There are 3 or more types that send the bendix gear out to engage the flywheel.

2) Starter is loose and needs to be tightened...and along these lines, the starter needs shimming.

There might be more possible causes but my memory ain't up to snuff.
 
As above, remove the plugs and try cranking. This sounds very much like water injestion to me.
 
Also, make sure the starter bolts are all tight and bracket/mounts are not broken . Can you yank on the starter and feel any give at all?
The pinion gear could be worn , or possibly even a chipped or missing ring gear tooth . Or some gomph may be preventing full extension of the Bendix to fully engage the pinion gear to the ring gear.
 
quote:
Originally posted by chriscraft67

As above, remove the plugs and try cranking. This sounds very much like water injestion to me.

Click to expand...

Would there be any other "symptoms" that I would be seeing if it were water ingestion?? Would the water eventually "burn off" after running for a while?? When I was running this, it was not in the water but had mufflers and hose running to it and it seemed to be running just fine.
 
quote:
Originally posted by Sandy

Also, make sure the starter bolts are all tight and bracket/mounts are not broken . Can you yank on the starter and feel any give at all?
The pinion gear could be worn , or possibly even a chipped or missing ring gear tooth . Or some gomph may be preventing full extension of the Bendix to fully engage the pinion gear to the ring gear.

Click to expand...

Sandy, I did have my hands on it while I was troubleshooting the electricals on it. It appeared to be pretty solid and did not move. I did read on an automotive forum that shim can be a big deal with the PMGR starters.
 
There are two issues. Only quarter turn cranking then jammed and spinning with out cranking. The quarter turn is what concerns me. What could cause the engine to jam??? Indeed there are a variety of drive problems that could cause the spinning but if the starter is not loose misalignment is less suspect as a cause of jamming.

Since the boat seems to be out of the water check for missing coolant and coolant in the oil as any other water will have drained down. The color and condition of the plugs are the best indicator of any water problems.

In any event pulling the plugs, inspecting and doing compression check is probably easier than getting that starter out. IMO replacingthe starter alone is probably not going to instill high confidance that all is well unless there is an obvious failure of the starter shch as broken nose casting.
 
You say that the engine does start and runs fine. If there's no water in the oil and the engine and drive seem to be working properly, my hunch is that the Bendix drive is bad, probably from a bad section in its windings. We used to find that often in auto starters. Decades ago, when I was a mechanic, we replaced many more drives than we did starters. Pulling the starter is a real pain, literally and figuratively, on Mercruisers. Once it's out, it's easy to check. If that proves it's bad, I suggest you replace it with a high-torque starter.They are lighter,smaller and easier to install. Make sure you replace the mounting bolts as well. Do not use plain bolts you can buy at any hardware store. Starter bolts have a knurled section in the middle to keep the starter in proper position. Good luck and let us know what you find. Hy
 
quote:
Originally posted by pdecat

There are two issues. Only quarter turn cranking then jammed and spinning with out cranking. The quarter turn is what concerns me. What could cause the engine to jam??? Indeed there are a variety of drive problems that could cause the spinning but if the starter is not loose misalignment is less suspect as a cause of jamming.

Since the boat seems to be out of the water check for missing coolant and coolant in the oil as any other water will have drained down. The color and condition of the plugs are the best indicator of any water problems.

In any event pulling the plugs, inspecting and doing compression check is probably easier than getting that starter out. IMO replacingthe starter alone is probably not going to instill high confidance that all is well unless there is an obvious failure of the starter shch as broken nose casting.

Click to expand...


Bruce, after the quarter turn it is not like the engine "jams", it seems to be more that the pinion engages for about a quarter turn and then
disengages and I hear whirring like it disengaged and is just spinning. There is nothing that indicates something is mechanically jjamming the starter that I am aware of. The boat I have is a '98 Mariah Z204...and the starter is somewhat accessible...the plugs are a completely different story. I had some work on it a few years back and told my mechanic to replace the plugs/spark wires to them since they were ridiculous to get to. A few are accessible but some are just impossible to reach unless I work for cirque du soleil.
 
...and the bendix gear itself may be going out. You should re-read what I wrote above
 
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