Engine mount adjustment nut is stuck.

[500dollar744ti]

It's a 1990 MCM 350 magnum, I just got the alignment tool for the boat I purchased less than a year ago and whaddya know, it's not aligned.

I'm starting by adjusting the front mounts 1/2 of a turn as the procedure calls for but the starboard side adjusting nut is stuck. I was able to free the pinch nut and I can even lift the engine some on that side to take the weight off the adjusting nut but it still won't budge.

I'm pretty resourceful but this is in an awkward position and I'd like to hear any tips or tricks. I have it soaking in PBlaster right now.

 

[muc]

Re: Engine mount adjustment nut is stuck.

Did you bend back the locking tab?

 

[500dollar744ti]

Re: Engine mount adjustment nut is stuck.

Yes I did. When I put force to it, the rubber part of the mount starts flexing but the nut doesn't break free. I don't want to break the rubber part of the mount.

 

[tpenfield]

Re: Engine mount adjustment nut is stuck.

Hopefully, the PB Blaster will work its way into the threads. Is the mount rusty, excessively rusty?

One thing you could do, if you are needing to adjust the nut upward, is to take some/all the weight off of the mount. I used a scissor jack to hold the engine up when I replaced the engine mounts on the 454 Merc. The same approach could be used to take some weight of of the mount.

 

[500dollar744ti]

Re: Engine mount adjustment nut is stuck.

Yeah, I was able to put a thick piece of wood down on my stringer and use a jack to prop up that side of the engine, I took all the weight off the mount and the stupid thing still won't turn. It's rusted stuck but it's not excessive, I was able to get the top bolt free which was in the same condition.

I may just have to remove the thing and put it in a vise, was hoping to avoid that.

 

[Bondo]

Re: Engine mount adjustment nut is stuck.

Yeah, I was able to put a thick piece of wood down on my stringer and use a jack to prop up that side of the engine, I took all the weight off the mount and the stupid thing still won't turn. It's rusted stuck but it's not excessive, I was able to get the top bolt free which was in the same condition.

I may just have to remove the thing and put it in a vise, was hoping to avoid that.

Ayuh,.... Unfortunately, it sounds like yer gonna Have too....

Put it back together, Greasy,...
Greasy steel don't rust,... Just like Greasy electrical connections don't corrode.....

 

[500dollar744ti]

Re: Engine mount adjustment nut is stuck.

Can I lift the engine off the mount to remove it without bothering the rear mounts?

 

[tpenfield]

Re: Engine mount adjustment nut is stuck.

My engine mounts looked like this . . .

No way would they turn.

I had to remove the mount base and arm from the engine block and then cut the nut off.

Ordered new mounts and greased them upon install, like Bond-o mentioned.

Don't lift the engine, else you will bust the transom mount and that will be totally expensive $$$$. Just support the engine enough and unbolt from the engine block and mount base.

Here is the new base and the mount arm prepped and painted . . .

 

[500dollar744ti]

Re: Engine mount adjustment nut is stuck.

Ahh, I see what you are saying, remove the whole bracket with the mount instead of trying to lift the engine over it.

It's been raining all evening but I'll try that out tomorrow. Mine aren't as rusty as the ones you pictured but I don't think I'll be able to free the nut without removing the mount.

Why do the mounts have such flimsy screws holding them down to the stringer, is that like just a locating type thing so they don't slide around?

 

[Bondo]

Re: Engine mount adjustment nut is stuck.

Ahh, I see what you are saying, remove the whole bracket with the mount instead of trying to lift the engine over it.

It's been raining all evening but I'll try that out tomorrow. Mine aren't as rusty as the ones you pictured but I don't think I'll be able to free the nut without removing the mount.

Why do the mounts have such flimsy screws holding them down to the stringer, is that like just a locating type thing so they don't slide around?

Ayuh,.... Generally speakin', they're 1/2" lags,...

 

[500dollar744ti]

Re: Engine mount adjustment nut is stuck.

So, I took the mount and bracket off today, what a terrible, terrible pain that was.

I supported the engine from the top but I was squeezing myself so far into the bilge to get at the lower bracket bolt that my neighbor came and asked if I was stuck.

I got the nut free but even that was painstaking. After running it up and down the threads with gobs and gobs of blue bearing grease, it finally started to move freely.

UGH, what a chore.

 

[tpenfield]

Re: Engine mount adjustment nut is stuck.

glad to hear you got it un-stuck. Took me all day to replace mine. Definitely a chore and a half.