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Jason
Jason, Marine Mechanic
Category: Boat
Satisfied Customers: 14299
Experience:  Degree in Marine Technology. Gas and diesel marine mechanic.
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Mercruiser 228, 305GM new starter won't engage ring gear.

Customer Question

Mercruiser 228, 305GM new starter won't engage ring gear. Second ew starter. 123/4 inch flywheel, all teeth look like new. Already sent old starter back for core. Have tried shimming the outside with 6 shims and this just barely touches the flywheel.. Am now machineing down the mounts to raise the starter into the ring gear unless you can give me another way to reinvent the wheel. thanks Tom
Submitted: 1 year ago.
Category: Boat
Expert:  Jason replied 1 year ago.
Hi Tom, Jason here.
What is the story here? Was it working fine on the old starter, and the replacement starter does not work?
Customer: replied 1 year ago.
old starter was corroded and needed replaced, 2 new starters now and neither work. One is the new smaller Quicksilver the other looks like an old GM heavy duty car/truck starter.
Expert:  Jason replied 1 year ago.
Can I get the serial number off your engine. And also the part number on the starters you got.
Expert:  Jason replied 1 year ago.
I'll check and see if you have the right parts or not.
Customer: replied 1 year ago.
Eng ser #(###) ###-####all verified on both the valve cover and the bell housing. Big new starter 806-965-A4 I think it is a sierra, the smaller starter is a *-M0090697 Quicksilver
Expert:  Jason replied 1 year ago.
Are the bolt holes on your starter straight across, or are they staggered?
Customer: replied 1 year ago.
straight across
Expert:  Jason replied 1 year ago.
I just looked it up and the correct part number for the starter is 50-806965A4 You wrote 806-965-A4 so that should be the correct starter. The question now is are you using a factory mercruiser starter or aftermarket made in china starters?
Customer: replied 1 year ago.
As far as I know the, the small one is the new style Mercruiser the large one is possibly a sierra / Delco. The starter at NAPA that is supposed to fit, matches these starters.
Expert:  Jason replied 1 year ago.
It looks like you requested a call on your end, was that something you wanted. Or did you want to stay online?
Customer: replied 1 year ago.
I just want an answer. the easiest way possible
Expert:  Jason replied 1 year ago.
I would get starter #50-806965A4 from an actual mercury dealer. There are only 3 types of small block starters. 1. There is the PGM type, also known as the mini, these are for 14 inch flywheels only 2. There is a direct drive type (big type) for 14 inch flywheels 3. And there is a direct drive type for 12 3/4 flywheels. And that is it, there is no 4th or 5th type. The 2 differences between the direct drive starters is the nose cone, and the gear. And that is it. With aftermarket starters you always take a gamble that the part is going to have a higher defect rate than a factory OEM part. And I would bet that the starter you have either has the wrong nose cone on it. Or, the box was mislabled and you simply have the wrong part. There isn't much guesswork here as there are only 2 different types of direct drive starters, 1 fits and one will not fit. On the starter you have now, the direct drive starter, either the nose cone or the gear on it is incorrect. (or both). Does that make sense?
Customer: replied 1 year ago.
That would make sense if both of these starters weren't mercrusier (Factory) starters. I thought the first replacement was wrong because it was sent as a Mercruiser GM starter from Overton / Gander Mountain but seemed to be a Sierra rebuild. I got the secind starter ordered by a tech directly from Mercruiser through iboats and L&M MarineLLC. This is , according to Mercruiser, the only starter for this engine, but it still misses the flywheel. That is why I tried to Shim thwe outside and am now ready to resort to machining the mount down so it will raise up into the flywheel. If you have no other ideas, don't feel bad, as supposedly the "best" have failed on this one.
Expert:  Jason replied 1 year ago.
Shimming moves the starter gear away from the flywheel, it doesn't move it closer to it. And you definitely don't want to grind the starter. If the alignment is off, or if the bolts are not torqued properly, the outside ear of the engine block that the bolt goes into will snap off. And then that would be the end of the block. The only other idea is the flywheel has loosened up on the crankshaft or the flywheel itself is warped. Again this isn't rocket science, there is only 3 starters types in total, and only 1 fits the 12 3/4 flywheel, the other 2 do not. Do you have an starter rebuild shop in your area?
Customer: replied 1 year ago.
The shims move the starter away from the flywheel if you shim both mounts. Shimming just the outside, moves the starter up closer to the ring gear. I used 6 shims a and just touched the flywheel. This was suggested by the starter rebuild shop. That is why I am ready to machine the mount instead of adding more shims and tweeking the whole mount.
Expert:  Jason replied 1 year ago.
Which starter are you trying to fit, the larger direct drive one or the mini PGM?
Customer: replied 1 year ago.
The mini (the last one from Mercruiser). I'm using it because it is much lighter and has more meat to the mounting so that it can be machined and still maintain it's structural integrity.
Expert:  Jason replied 1 year ago.
Okay the mini will not work with 12 3/4 inch flywheels, I covered that above. You need the larger direct drive starter. Go to a starter alternator rebuild shop and ask them to show you a delco direct drive starter for both the 14 inch flywheel and the 12 3/4 inch flywheel. You will see there are spacing differences in the nose cones where the starter fits. The correct starter for your engine, as long as you are sure you have a 12 3/4 flywheel is going to be 50-806965A4. And I am not saying this in a rude way, but that is the end of story. that is the correct starter for that engine. I definitely have no reason to lie to you or make stuff up. And I do implore you not to machine the starter and try to "make" it fit. The outer ear of the engine block will likely crack, ruining the bock. I could not tell you how many times I have seen broken blocks because incorect starters were used, and starter bolts that were not torqued correctly. I change probably 30 inboard starters year, there are only the 3 different ones, and if you get the correct one you should have absolutely zero difficulties. Does that all make sense?
Customer: replied 1 year ago.
I am also not being rude, but I have 2 invoices sitting in front of me with that part number on them and in fact Mercruiser has upgraded to part # ***** I already took this to the starter rebuild shop and to NAPA, O'riellys and the local Mercruiser shop where I was told either one of these, was the correct starter. This smaller starter is marked Quicksilver and came directly through Mercruiser tech at phone # ***** Like I said, don't feel bad as they idi not have the answer either. The starter rebuild told me to machine the mount. One more note: Weither it is an old wives tale or not, I was told that in the late 70's early 80's that a block supplier for the GM 305 heavy duty blocks, miss-bored the mounting on some blocks. Most were used in trucks and taxis and would no longer be around, which would account for this being a unique problem. This boat was a weekend Coast Guard boat and hasn't been in service for over twenty years, asd it was replaced by a larger boat.
Customer: replied 1 year ago.
Are we done?
Expert:  Jason replied 1 year ago.
I look up parts on the Mercruiser dealer network and that is calling for 50-806965A4. So if you walk into any dealer, they are going to give you that part number. I punched in 8M0090697 as well as 50-8M0090697 and got no results. For the heck of it I punched 8M0090697 into google and go all of 38 hits. 38 hits on the entire internet. And all of the hits were all garbage, links to garbage parts sellers. So i'm not sure what you have got there, but I can't find anything on it. Questions never close here. So monday call a local dealer and give the your serial number and see what they offer you for a starter. It is going to be the number I gave you. Again there is no guess work here. Only 1 starter fits that engine, and it is the one listed. Think about it, your old starter was direct drive, and that worked just fine. Does that make sense? Why don't you post back tomorrow after you have had a chance to call a dealer. I'm sure they will validate the help I have given you here today.
Customer: replied 1 year ago.
What you say makes sense, however these parts were from mercrusier. The Mercruiser dealer, just last week compared these starters and talked to Mercruiser tech. and verified that they were correct. The flywheel is fine and is 12 3/4 inch. That new # ***** gave you came directly from Mercruiser and most dealers don't even have the super-cede yet. Everyone that has worked this problem has seen that they are the correct parts as listed, but have to concede that they just don't work for some reason. This is simple mechanics and when I measure everything up, the pinon gear just misses engaging the flywheel. Math doesn't lie. If I had'nt sent in the "old" core, then I would have an answer. This is just an anomaly that I will have to fix using shade tree mechanics.
Expert:  Jason replied 1 year ago.
What was the deal on the original starter that was in there? Did that ever start the engine? Did you ever see it start the engine?

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