cant budge mercruiser 165 hp from its rear mount

[bob johnson]

I am pulling a 6 cylinder 165 mercruiser from my 1971 starcraft islander. the heads of the two rear mount bolts9 3/4 socket) sheared off trying to turn them.....I tried to hammer the broken shaft downward...didnt seem to budge...i caN FEEL A NUT ON THE BOTTOM SIDE. I have a chain hoist on the engine now....the front mount is not attached to anything , the floor is gone.... i have diusconnected everything else... the outdrive is out.....the motor wont budge off those two mounts...

am I missing something? is it possible it is a super tight fit and it corroded together? i had hammering the side of the transom side of the mount while the front was 3 " off the floor...in the hopes it would break the connection...no go


do i need heat? or is that bolt some special shape i dont know about?

thanks

bob

 

[dozerII]

Re: cant budge mercruiser 165 hp from its rear mount

Hey Bob , the rear bolts have a captured aluminum nut in the transom assembly. Pounding on them may break something down there. How far down did the bolts break off? Under the head of the bolt there should be a flat washer, aluminum spacer, then under the mount there will be a double wound spring washer and a fiber washer. You may be able to put a pry bar between the upper and lower mount to break it loose.

 

[achris]

Re: cant budge mercruiser 165 hp from its rear mount

Last resort (and you may be there already) is to take a hacksaw and cut the bolt between the flywheel housing and the inner transom plate . As already suggested, the nut may be captive. Some of the earlier ones weren't, but the later ones definitely are. Pounding on it will only break something you really don't want to break. It sounds like the bolts are rusted/seized inside the rear mount (which is pressed into the flywheel housing)...

Chris.......
(All the engines I install get a very liberal coating of a high quality water-proof grease on all those sorts of nuts and bolts. For this very reason.)

 

[bob johnson]

Re: cant budge mercruiser 165 hp from its rear mount

the heads of both bolts broke off maybe 1/4 max above the bell housing surface.. the big stainless steel washer fell to the bottom of the boat and there was a rusted crumpled layer of some that was dissentigrated all around the bolt shaft..i had thought it might be a rubber/steel bushing....but that the bolt should be able to be driven down through it....

I am actually unloading all that stuff...but i didnt want to break or cut anything just in case i can find someone interested....I had an ad in craigslist for the free motor outdrive and transom gimbal assy......but noone has called and i want to move on...
so is there a captive nut inside the bell housing ?? or is it down in the transom assy? is the nut captured?? thats why i cant drive it and the broken bolt down?

thanks

bob

 

[achris]

Re: cant budge mercruiser 165 hp from its rear mount

the heads of both bolts broke off maybe 1/4 max above the bell housing surface.. the big stainless steel washer fell to the bottom of the boat and there was a rusted crumpled layer of some that was dissentigrated all around the bolt shaft..i had thought it might be a rubber/steel bushing....but that the bolt should be able to be driven down through it....

Already been explained, twice.... There is a captive nut that will prohibit the bolt being driven down.

I am actually unloading all that stuff...but i didnt want to break or cut anything just in case i can find someone interested....I had an ad in craigslist for the free motor outdrive and transom gimbal assy......but noone has called and i want to move on...
so is there a captive nut inside the bell housing ??

No

or is it down in the transom assy? is the nut captured??

Again, yes.

thats why i cant drive it and the broken bolt down?

The bolt broke off because the shaft of it is rusted solid in the rear mount. You can't drive it though BECAUSE THERE'S A CAPTIVE NUT ON THE END....

Simple statement here now.... You have very little choice... Cut the bolt through (between the bottom of the mount and the top of the inner transom plate mounting pad with a hacksaw or a gas-axe.... Apart from the bolt, you'll be damaging nothing else. Then drive out the complete rear mounts and replace them...

Chris......

Chris.......

 

[bob johnson]

Re: cant budge mercruiser 165 hp from its rear mount

thanks......i have a sawsall... hopefully there is room for the saws travel...is there any chance one of you know the weight of this 6 cylinder?

bob

 

[Bt Doctur]

Re: cant budge mercruiser 165 hp from its rear mount

Another option is to heat the bolt untill it melts away from the rubber and lift the engine out.Then remove the remaining part of the bolt from the housing.
About 300 lbs I think

 

[bob johnson]

Re: cant budge mercruiser 165 hp from its rear mount

since i just found out, I doint have any acetylene.... I am going to have to cut it with a sawzall.... and it has to weigh a lot more than 300 lbs......I am thinking at least 400 lbs......man I checked the eb for a while now and all i found was the weight of the motor and outdrive assembly together...650 lbs

bob

 

[achris]

Re: cant budge mercruiser 165 hp from its rear mount

All you need to know is that it's heavy and you need a chain block. You can't lift it on your own.... (or with a strong friend)... Nowhere on any documentation do Merc give engine weights.... Total package weight, yes, but not stand-alone engine weight.

 

[bob johnson]

Re: cant budge mercruiser 165 hp from its rear mount

I have a nice ratcheting chain hoist that is rated for 1000 lbs.... so I am good to go...

bob

 

[achris]

Re: cant budge mercruiser 165 hp from its rear mount

I have a nice ratcheting chain hoist that is rated for 1000 lbs.... so I am good to go...

bob

1/2 ton... That's all I use, and I've lifted fully assembled V8s....

 

[bob johnson]

Re: cant budge mercruiser 165 hp from its rear mount

what a bear of a job...was lifting the boat and trailer and me!!!off the ground. the boat and trailer was swinging in the air!!...the dang motor would not come off the mounts.....i know on the port side it seems that even if I used a hack saw, I could only cut 1/2 way through that bolt before I started cutting the bell housing/mount boss on the inside...i used a floor jack on plywood under the motor,...and freed up the bind the starboard side ...but when i tried that on the port side the transom plate cracked...it didnt want to budge...I used a mapp gas torch and that help and it finally popped in my face once i broke that binding with the torch.....thanks for the help guys...at bleast i knew to hang in there and there wasnt a bolt I was missing somewhere holding this up.

bob

 

[bob johnson]

Re: cant budge mercruiser 165 hp from its rear mount

some pictures:

this was the starbord side.... that budged after i applied some heat.... you can see the two dias, the inner is the bolt itself, the other is whats left over from some bushing...must have had a metal ID sleeve...I think that bushing, is what prevented me from driving the bolt dowm.. now that i have the transom assy in hand, i can see that while the nut is captured not would prevent from being driven DOWN, only that it would rotate!

if i had thought to hammer just the bolt shaft( with a punch) then i might have driven it out...MIGHT...i tried to cut it with an angle grinder...but the wheel dia wasnt sufficient to go all the way through before i hit the bell housing frame with the grinder head.

here is the other side, that came last and held tight i eventually cracked the transom plate trying to lift the motor off this broken bolt.... it was under pressure from the jack, when i heated it and it popped eventually.....sooo a little tid bit...heat is your friend....

thanks again...

is there anything that is worth while saving off the transom plate that people look for?

bob