Motor Mount Broken - I think

[mejim707]

So I was putting my exhaust back on and when I grabbed it make sure it was secure the entire front of the engine, closest to the gas tank, lifted about an inch. The engine is crazy light but what the heck!

I think the engine mount closest to the gas tank is broken. But I can't see any signs at all of broken parts, rubber, rust anything that would suggest it's broken. Other than of course the freaking engine lifted. I tried it again to be sure I wasn't wrong and it moved again.

It doesn't seem to move side to side but definitely up.

Any suggestions? If I have to replace the mount do I need to also realign the engine? I'll check if there's any side to side motion at all tomorrow but it doesn't seem like it. Only up and down.

Anyway, this could be it for this year. I don't really have it in me to pull the engine and realign everything.

And t think, I was going to get out on the lake tomorrow for the first time this year.

 

[Michael Hunt]

The engine mounts will separate in time, but its odd that you were able to pull the engine up.

What kind of boat do you have?

Lifting the front of the engine that much would suggest that more than one engine mount is compromised. Unless the engine-to-engine cradle bolts backed out somehow.

 

[mejim707]

The engine mounts will separate in time, but its odd that you were able to pull the engine up.

What kind of boat do you have?

Lifting the front of the engine that much would suggest that more than one engine mount is compromised. Unless the engine-to-engine cradle bolts backed out somehow.

Hey thanks for the reply.

It’s a 96 Challenger with single 787. I should have mentioned that.

Yeah I can’t see any signs of a broken part.

When you say the engine to engine cradle bolt what are you referring to?

 

[Michael Hunt]

The base of the rubber part of an engine mount is metal, nothing would look broken, but if you lifted the engine, it would go back down where it came from concealing the problem.

How does your engine mount to the hull?

I have to admit that I have the 720 engines and they use an engine cradle between the engine and the motor mounts, the 787 engines are probably different.

 

[mikidymac]

Use a pry bar and see if the engine mounts separate. You should not have much engine movement at all. Definitely not "and inch".

 

[mejim707]

Use a pry bar and see if the engine mounts separate. You should not have much engine movement at all. Definitely not "and inch".

I'm going to record it today. It definitely moves upward without much difficulty.

If I have to replace the mount, is it possible to do so without removing the engine? I believe I'd have no choice but to remove the exhaust again but what other issues could I run into do you think? I must have been running it with this issue for a while last year.

 

[mejim707]

Also, will I need to realign the engine? I don't thing there is any side to side movement so I technically should be able to mark the current position then replace the mount in that same position? One thing after another.

 

[mikidymac]

You really should align the engine whenever messing with engine mounts.

 

[mejim707]

You really should align the engine whenever messing with engine mounts.

Where can I get the alignment tool? Amazon?

If I have to pull the pump again so be it.

 

[mikidymac]

I think SBT might be one of the few places still selling them.

 

[mejim707]

I think SBT might be one of the few places still selling them.

Ok found the alignment tool on SBT and I'll purchase it tomorrow. Should have it by mid next week.

I know I can replace the mount without removing the engine. Stinks I have to pull the pump to realign it but whatever, is what it is.

My only question now to myself, is if I should just pull the engine completely since I'm pulling the pump, and exhaust yet again. SBT has the premium on the site for about $1500 + $250 shipping.

 

[mejim707]

There’s zero side to side movement with this broken mount so I’m not certain I need to realign the entire engine if I properly mark the current position before replacement.

Based on this, did the inside of the mount separate? This is bazaar to me. It looks like what I thought was a full rubber part is actually hollow with a cap on top?

Here is a video of the broken mount
Broken Mount

 

[mejim707]

I have the new mount, alignment tool (just in case) and exhaust gasket on the way. I'll get this all in the following weekend. I should be on the water in a few weeks.

The lake here gets gnarly with waves but sometimes they come out of nowhere and by the time the reach you it's too late. They get massive. So I'm certain I hit a wave and that mount couldn't handle it.

 

[mejim707]

I think SBT might be one of the few places still selling them.

Hi, I hope you're doing well. I finally replaced the mount and took your advice to get the alignment tool and proceed with a realignment. I believe I have it correct. Can you look at this video and let me know if this is what we should expect?

This is with 3 thicker shims under both rear mounts and no shims on the front mount. All mounts are torqued to 18 foot pounds.

Completed Alignment Video

 

[mejim707]

@mikidymac does that video above look good on the alignment? This is the first one I’ve ever done. I have the plate bolted up, the brass guide in place and the long rod slides into the back of the PTO fully without resistance.

If this is happening smooth, does that suggest the alignment is perfect?

Incidentally, when I first checked before messing with the mounts the alignment was WAYY off. The previous owner or his mechanic had no clue what they were doing. I’m slowly dialing this old girl back into spec. I love this boat lol