starting problem 4.3L Mercruiser

[NMBuzz]

I have a 1993 Larson 17' with an I/O 4.3L Mercruiser 2bbl/ Alpha One drive.
I have a problem with the starter engaging reliably.

A little (pertinent) history- when I bought the boat I had a shop change the gimble bearing, exhaust and shift bellows, and impeller. The starter was frozen so I had them go ahead change it out (new ARCO starter with offset bolt pattern). Long story short... after getting it back from the shop (to get water out of the fuel tank, and do other repairs) I was able to start it but the starter sounded like it was grinding. I noticed the outer starter bolt hole on the block is half there which exposes half of the outer starter bolt, however it does tighten and holds 50 foot pounds of torque.

Of course the "shop" knew nothing. Not sure, but NO more business there...

The continuing problem I am having is this. When the motor is cold I can get the starter to catch and start, but it grinds. When the motor has been running and is hot, the starter grinds a lot worse and sounds like it is not meshing with the ring gear. The bolts remain tight and there is a slight movement of the starter but it is grinding like heck! I have pulled the starter and I found the flywheel teeth to be chipped in places, and slightly ground down in others and OK for the most part. I tried shimming the outer side of the starter (.120") to get the bendix in tighter and it seemed to help, but not when it is hot. I can turn the harmonic balancer to get past the "bad spots" on the ring gear, but when it is hot the starter just won't catch or engage and it REALLY grinds. If I let it cool for a few hours I can "get lucky" and it catches (but still sounds "bad").

I am going to pull the motor and replace the ring gear, but I am wondering about the broken bolt hole. I cannot believe I may have to change out the entire block for this one thing. On the other hand it makes more sense to me and is cheaper to change the ring gear, and rebuild the starter drive gear and get a better look at what is going on in there..... The starter had slight movement initially and I thought a good thing to do would be to add additional support (due to the broken bolt hole) to the starter so I made and installed a starter brackets for it. Seemed to help...

I have not pulled the starter back off yet, but I plan on finding a worn down drive gear (which I aim to replace). Could the slave solenoid up by the carburetor be part of the (thermal) problem?

Any thoughts on this?

Sorry for the long post, but I want to give as much information and history as I can think of. I am new to boats but not to motors and such.

 

[maxxman04]

Re: starting problem 4.3L Mercruiser

start by replacing the ring gear and starter. you should be able to drill thru the broken bolt with a smaller drill bit, then use an "E-Z OUT" type tool to remove bolt. starter should not have any movement at all when bolted up, but if it does you should be able to buy shims at parts store.

 

[NMBuzz]

Re: starting problem 4.3L Mercruiser

start by replacing the ring gear and starter. you should be able to drill thru the broken bolt with a smaller drill bit, then use an "E-Z OUT" type tool to remove bolt. starter should not have any movement at all when bolted up, but if it does you should be able to buy shims at parts store.

Actually the bolt hole in the block housing is what is broken, not the bolt. Thanks for your quick reply and help!

 

[maxxman04]

Re: starting problem 4.3L Mercruiser

proof that speed reading doesn't work. my bad. :redface:

 

[NMBuzz]

Re: starting problem 4.3L Mercruiser

LOL! No worries!

 

[maxxman04]

Re: starting problem 4.3L Mercruiser

if it holds fine, may not worry about it. keep eye on it for sure tho. you MIGHT be able to have a new surround welded, but that would mean taking engine out of boat.

 

[buddybarnhill]

Re: starting problem 4.3L Mercruiser

dont know much about boat engines but alot about cars one thing is make sure that your starter teeth line up correctly with the flywheel and also the shop may have jipped you they could have put a rebuilt peace of crap starter on there and charged you for a new one i would take it back and demand a repair or new starter if it was a brand new starter it should have some kind of warranty

hope this helps.....

 

[NMBuzz]

Re: starting problem 4.3L Mercruiser

dont know much about boat engines but alot about cars one thing is make sure that your starter teeth line up correctly with the flywheel and also the shop may have jipped you they could have put a rebuilt peace of crap starter on there and charged you for a new one i would take it back and demand a repair or new starter if it was a brand new starter it should have some kind of warranty

hope this helps.....

I actually bought the (new, not rebuilt) ARCO marine starter myself and took it to the "shop". I did go back to where I purchased it from and it was the "right one" and they are a reputable place.

My biggest concern is that broken bolt hole in the block housing holding. I do know that cast is hard to "fix".... but the motor is coming out anyway...
Thanks!

 

[maxxman04]

Re: starting problem 4.3L Mercruiser

if you know how to weld, it's not hard. or take motor to good shop, they should be able to fix, since motor is coming out anyway.

 

[NMBuzz]

Re: starting problem 4.3L Mercruiser

if you know how to weld, it's not hard. or take motor to good shop, they should be able to fix, since motor is coming out anyway.

Yep, that's the plan. Thanks to all who replied.

 

[NMBuzz]

Re: starting problem 4.3L Mercruiser

I pulled the motor today and got the flywheel off. I went to NAPA after I came up short at the marine shops here in the desert. The flywheel from NAPA has the exact dimensions (168 teeth, 14") and bolt holes. Only problem is it is a little thicker ~<1/2". Is this a problem? I have read and heard that an automotive flywheel will be just fine but I am looking for an expert opinion!

 

[buddybarnhill]

Re: starting problem 4.3L Mercruiser

shouldnt be a problem at all the thickness should not matter even so im sure yours was 1/4 originally so so a couple of centimeters wont hurt at all

 

[maxxman04]

Re: starting problem 4.3L Mercruiser

thickness may matter when it comes to your coupler/driveshaft. and engine balance. be absolute certain, as this is all "he said" to me. hate ta see all that work and money leave ya stranded.

 

[buddybarnhill]

Re: starting problem 4.3L Mercruiser

thickness of a flywhell should not matter at all all it is there for is starting purposes other than that its a finely tunned and balanced piece of metal that is gonna spin wheather is 1/4 inch or 1/2 an inch

 

[Bondo]

Re: starting problem 4.3L Mercruiser

Ayuh,... Why are you replacing the Flywheel,..?? When you only need a Ring Gear,..??

 

[NMBuzz]

Re: starting problem 4.3L Mercruiser

Ayuh,... Why are you replacing the Flywheel,..?? When you only need a Ring Gear,..??

It sure looks like it is a one piece flywheel. If the ring gear was replaceable it would have screws or bolts right? Or, is the ring gear pressed onto the flywheel somehow? I have looked at this thing and it sure looks like a one piece unit. I really am stuck here. When I lay them down next to each other on a flat surface the ring gear on the new flywheel puts the teeth farther from the satrter. Judging by the starter gear marks on the old wheel this would mean the starter barely engages!?!? I will try to take some pictures.
Thank you for your help.
Brian

 

[NMBuzz]

Re: starting problem 4.3L Mercruiser

No, if you heat the ring gear a bit (expand it) you can knock it off with a hammer. In fact you can probably knock it off without the heat if you have a big hammer. (A cheap propane torch will work fine.) To put it on, put the new ring gear in the wife's oven at 350 degrees for 20 minutes. Should almost fall into place.

As to the busted bolt hole in the casting, I would get a bolt and thread it in from the back side and use it as a stud to mount the starter. Put some serious lock tight on it (you do not ever want it coming loose if you have to change the starter again.) and tighen it down, HARD. You might even consider doing a little brazing to the head of the bolt so it never comes loose.

Bottom line, the starter can not be allowed to move at all. Not even a little...

Thanks for that reply. That sounds like a great idea to use a stud instead of a bolt. I am off to get a ring gear. Thanks again to all the advisors out there! This is a great forum!

 

[NMBuzz]

Re: starting problem 4.3L Mercruiser

OK- Got the ring gear issue resolved thanks to the guru's that replied to my thread. I cannot thank you enough!

Now the root of the problem- the casting for the starter bolt hole. I attached some pictures (I hope-computers are not my specialty LOL). I tried the bolt for a stud idea with a 3/8" all-thread, however I don't think this is going to work as the starter would have to be slid up the bolt then spun 90 degrees to enter the flywheel housing. Not to mention the flywheel cover would have to stay off, or be cut away- either way i don't have enough room in the boat when the motor is in. Great idea it was though! I am off to a buddies house to braze the piece back on, then locktite!:redface:

 

[NMBuzz]

Re: starting problem 4.3L Mercruiser

I feel kind of silly posting to my own posts, but in the spirit of the forums rules I am keeping an update. Hopefully the information will help someone to have a few less headaches than me.

Took the block to a shop that the owner has repaired several of the same. He uses nickel on a MIG setup and re-taps it (3/8 x 16). Hopefully be done by mid week, and with the starter brace I can kiss this problem good bye!

 

[NMBuzz]

Re: starting problem 4.3L Mercruiser

Just to close out this thread- I got the block fixed, changed the ring gear, and put a new bendix drive gear on the starter (and sealed the openings in the solenoid with RTV to prevent any arcing) put it all back together and it made ALL the difference in the world.

Thanks to all who helped. This is a terrific forum!!!!!!!!!!!!