broken starter motor mount

[thrasher]

Okay everyone, another question!

I purchased a Glastron boat 3 weeks ago (my first ever boat and thought I did a pretty good job checking it over!). I have used it twice (each time for about 3 hours). On the second outing the starter motor would spin up but not turn the engine over. I assumed it was a defective starter motor.
When I got home I went to remove the starter motor and I found an unusual problem. I fear this is an engine out job to fix, but wanted to ask your advise.
The engine is a 1991 4.3L V6 Mercruiser 262CID.

The starter motor bolts to the engine with 2 long (approx 4") bolts in an offset pattern. The bolt nearest the engine is fine, but the bolt furthest from the engine is missing. The reason its missing is that the engine casting that should go over the bolt hole and have a tapped hole in it for the bolt to enter, has been broken off at some time!! The starter motor was held in place by one bolt, the casting of the starter motor could not take the twisting force when the starter motor turns and has broken the starter motor casing around the bolt hole, this has caused the gears on the flywheel and the starter motor to no longer mesh!
I have purchased a mercruiser remanufactured starter motor, but do not want to mount it with only 1 bolt (as it will just break again). I have been trying to work out the correct position of the starter motor (as it can pivot a long way on the one bolt) to get correct gear mesh, but I suspect that without removing the engine from the boat and then removing the stern drive to be able to see the flywheel and starter gear, I will not be able to get the starter motor correctly aligned. I am going to try and build up a new casting mount (using my arc welder) but again it will be very difficult to correctly drill and tap the hole without removing the motor (which I don't want to do!).
Is this a common problem on the Mercruiser 4.3L engine, or has a Gorilla owned this boat in the past?
Any suggestion on how to align the starter motor, or fabricate a new mount for the second bolt hole would be appreciated!! And I will appreciate it even more if it doesn't involve removing the engine!!
My garage roof is too low to get an engine hoist in, plus I don't own an engine hoist that will go high enough to lift the engine out (probably needs to be a chain hoist!!).

Gary

 

[stevieray]

Re: broken starter motor mount

Sounds like you bought yourself a real doozy there (what with all your wiring issues & all)! I don't know how that could have broken in the boat - the bolt should have failed before the casting if it was over-torqued by some gorilla. Maybe the engine was out at some time & it was busted (or dropped) then? Unless you have a lot of room to work, I think it will have to come out to be repaired properly.

 

[Windykid]

Re: broken starter motor mount

Might as well pull it out. Had you done any compression test to it lately? How many hours are on the motor? Is it worth repairing or put a short block in?

 

[Woody-jh]

Re: broken starter motor mount

I had the same problem two years ago, same engine. In my case, the flywheel ring gear was damaged as well. My repair bill that time included a new ring gear, new starter, (engine pulled out, etc) and a "JB epoxy weld" on the broken casting. It lasted two outings. Next repair was a short block...I am not a JB fan for starter casting mount repairs...

 

[bruceb58]

Re: broken starter motor mount

Besides a gorilla putting on the bolt it is possible you had some water intrusion that caused the engine to lock on you...thereby breaking the casting.

Any water in your oil?

 

[thrasher]

Re: broken starter motor mount

Thanks Guys,

I changed the engine oil, there was no water in it.. The engine has very low hours, I have a receipt for it, it was new 2 years ago and the owner said he has not done more than 30 hours with the new engine. It certainly runs well, no smoke, the oil looks a nice colour.. So I believe its in good health (except for the starter motor mount), but I have not performed a compression test (and can't until I fix the starter motor problem!).
Regarding the wiring, I bought the boat knowing the wiring was a mess (got a reasonable price because of the wiring!). The starter motor is the unplanned suprise!!
I am reallt loathed to take the engine out (just because I will have to pay someone to do it as there is not the room in my garage to do it. I don't trust anyone to service any of my vehicles as there are so many cowboys out there..

I will look a bit more, but may have to give in and get the engine out..

Thanks Gary

 

[wakeboarddude]

Re: broken starter motor mount

I feel your pain.... I had my engine rebuilt this winter and after putting it all back together i have a similar problem after two days out on the water. Since i have owned my boat (4years) there has only ever been one bolt on the starter, and one on the back of it to hold it tight in. never been a problem before so while the boat was out i didnt think to check it for a 3rd bolt. Well now that my engine has good compression, the starter won't hold its alignment with the flywheel. Its starts to turn over the engine then slips. There is a place for a third bolt but it appears that it is broken off inside the bolt whole. As much as I'd love to just quick fix it, i know that i have to remove the engine to do a proper fix, drill it out and re-thread it.
As much off a pain in the butt it is, your engine should probably be pulled out of your boat to do a totally proper job. Good luck!

 

[Cptkid570]

Re: broken starter motor mount

I'm trying to think whether or not there is a way to clamp the starter on there or an extra support (maybe through the other end of the starter) just to hold it tight enough so that you can test to see if the starter is in the appropriate spot, and then weld.

Do you have a tree anywhere? You could also built a swing-set looking hoist out of wood and use a come-along (cable puller) to jack the engine out..

 

[Windykid]

Re: broken starter motor mount

You could built a bracket to run off the head and bell housing and etend to the starter, just dont think it will wind up being reliable.

 

[thrasher]

Re: broken starter motor mount

I was thinking of putting a block of wood between the starter motor and the sump pan to prevent the starter rotating around the one mounting bolt and dissengaging the gears. But the previous starter cracked due to the turning torque produced when the motor tries to turn the engine over. So I still need to find a way to use the second bolt mount just to prevent the torque (twisting) from cracking the casing again. I am thinking of making a steel bracket that hangs of one of the bolts that mounts the stern drive to the flywheel housing and using that to take the second bolt, just not sure it will be strong enough..

Gary

 

[Fishermark]

Re: broken starter motor mount

I know small block chevy engines have an optional bracket for the back of the starter that holds it to the block. Here's a picture: I don't know if the 4.3 liter engines have the boss on the block, but I suspect they do.

 

[Coors]

Re: broken starter motor mount

yep, might get you through the season, but alot of brackets will be invovled without a new block.

 

[thrasher]

Re: broken starter motor mount

Well you will see in my new post "water in the engine" that I managed to MIG weld up the second mounting point and drill a 10mm hole throught the mount. This allowed me to use a longer bolt with a nut on top to secure the starter motor. So I now have two bolts mounting the starter motor.
Unfortunately the starter motor could not turn over the engine, so I decided something else was wrong.. First thought was a hydralic lock (cylinders full of water) so I removed all 6 spark plugs and a load of water came out the right hand bank of cylinders..
The starter motor now turns the engine over beautifully and my mount seems to have proved itself so that part is good. I bought this boat with the idea of using it for 1 year to see if I like boats and to learn how to look after them (I won't be as upsett damaging a $4K boat as I would damaging a $20K boat!). I still intend to sell it after 1 year, but I am confident my fix will last considerably longer than that!!
Unfortunately I now need to find the source of the water!! Oh yes the source was the lake but how did it get into my engine?

Gary

 

[Limited-Time]

Re: broken starter motor mount

If I had to guess I'd say the water intrusion caused the starter problems. It's not likely the starter would sheet the bed on a healthy engine.

 

[thrasher]

Re: broken starter motor mount

I completely agree. OI suspect water entered the engine, that locked the engine and then when I tried to start the engine the starter motor failed because the engine was locked and that put too much pressure on the starter motor, which caused the starter motor casing to crack!! The starter motor only being mounted with one bolt didn't help!!

Gary

 

[sunbird96]

Re: broken starter motor mount

see if their is enough room to weld a sted in. see if u can drop the starter 4 inches streight down. if u can weld in a stud with a nut and bolt.
done this with a chevy engine.

 

[bruceb58]

Re: broken starter motor mount

see if their is enough room to weld a sted in. see if u can drop the starter 4 inches streight down. if u can weld in a stud with a nut and bolt.
done this with a chevy engine.

The starter can't drop down so you can't to that.

 

[dhundeby]

Re: broken starter motor mount

Well you will see in my new post "water in the engine" that I managed to MIG weld up the second mounting point and drill a 10mm hole through the mount. This allowed me to use a longer bolt with a nut on top to secure the starter motor. So I now have two bolts mounting the starter motor.
Unfortunately the starter motor could not turn over the engine, so I decided something else was wrong.. First thought was a hydraulic lock (cylinders full of water) so I removed all 6 spark plugs and a load of water came out the right hand bank of cylinders..
The starter motor now turns the engine over beautifully and my mount seems to have proved itself so that part is good. I bought this boat with the idea of using it for 1 year to see if I like boats and to learn how to look after them (I won't be as upset damaging a $4K boat as I would damaging a $20K boat!). I still intend to sell it after 1 year, but I am confident my fix will last considerably longer than that!!
Unfortunately I now need to find the source of the water!! Oh yes the source was the lake but how did it get into my engine?

Gary

I have the same broken casting problem on my 2000 4.3L Mercruiser. Just wondering if your fix is still working. What are the details on the mig welding that was done? Have you ever tried "77" rods? Thank you. Dave

 

[bruceb58]

Re: broken starter motor mount

You should start your own thread instead of posting onto a 3 year old thread. You will get more responses that way.