Where are the rear motor mounts on a mercruiser 120?

[dave8311]

Not at all, sounds like top of motor or an accessory hitting something.

 

[Mike Lukacevic]

But does it need to come out? Could be wrong but noise doesn't sound like a rod or main bearing.

Well, Scott. I’m gonna follow your advice and not yank it out. A pal of mine that also works on boats and British cars like me said to just run it.
I was getting paralysis by analysis. I’ll post an epilogue. Maybe get towing insurance. I’m old. I’ve earned it.

 

[Scott06]

Well, Scott. I’m gonna follow your advice and not yank it out. A pal of mine that also works on boats and British cars like me said to just run it.
I was getting paralysis by analysis. I’ll post an epilogue. Maybe get towing insurance. I’m old. I’ve earned it.

Oh if you have British cars you must know all the local towing companies already....

Seriously would be curious to see what it was when you figure it out.

 

[Scott Danforth]

Could be loose flywheel..... Could be upper end...... Could be coupler....... Could be u-joints..... Could be bad flapper

 

[Mike Lukacevic]

Oh if you have British cars you must know all the local towing companies already....

Seriously would be curious to see what it was when you figure it out.

Hardy har. Never been stranded. Limped home the Pittsburgh Grand Prix once. Embarrassing. But when I figured it out it was a 2 cent tabbed washer on the throttle shaft it’s run perfectly.
Just like this boat will when I locate that 2 cent part. Thanks Scott

Could also check vacuum if you're thinking cam lobe. Exhaust flappers can sound like that. Or exhaust leak.

i haven’t seen a vacuum line on this motor yet

 

[Mike Lukacevic]

Could be loose flywheel..... Could be upper end...... Could be coupler....... Could be u-joints..... Could be bad flapper

Like the Wells Fargo wagon. It could be anything
I’ll figure what all these are and diagnose until my brain melts. Mike

 

[nola mike]

i haven’t seen a vacuum line on this motor yet

Make one...

 

[dubs283]

i haven’t seen a vacuum line on this motor yet

You're thinking automotive

Older marine engines don't use vacuum aside from a possible vacuum monitor guage on the dash

No emissions control, no vacuum advance

 

[Scott Danforth]

i haven’t seen a vacuum line on this motor yet

there are no vacuum lines on a marine motor

 

[1985 Century Mustang]

If your having problems removing the rear motor mount bolts (inbox me) I can definitely give you some crucial advice. I recently removed my 1985 mercruiser 140hp last week, it was a real pain in the effing ass, but I eventually got the bolts out with that dang nut that's located under the rear transom plate housing, and removed the engine. Omfg it was so nasty. I'll save you a lot of time and grief. Inbox me if you need some pointers.

 

[1960 Starflite]

If your having problems removing the rear motor mount bolts (inbox me) I can definitely give you some crucial advice. I recently removed my 1985 mercruiser 140hp last week, it was a real pain in the effing ass, but I eventually got the bolts out with that dang nut that's located under the rear transom plate housing, and removed the engine. Omfg it was so nasty. I'll save you a lot of time and grief. Inbox me if you need some pointers.

Why not share with the rest of us? Including me, they're a lot of "140" owners here

 

[Scott06]

Why not share with the rest of us? Including me, they're a lot of "140" owners here

Would actually be any Mercruiser owner of that vintage rear mount style... they all us the same rear mounting system. Usually a lot of heat and penetrating oil

 

[Mike Lukacevic]

If your having problems removing the rear motor mount bolts (inbox me) I can definitely give you some crucial advice. I recently removed my 1985 mercruiser 140hp last week, it was a real pain in the effing ass, but I eventually got the bolts out with that dang nut that's located under the rear transom plate housing, and removed the engine. Omfg it was so nasty. I'll save you a lot of time and grief. Inbox me if you need some pointers.

Thanks soooo much. Mine is really tight and I sure could use a few tricks if/when I pull it. There’s never an easy way.

 

[Scott06]

Thanks soooo much. Mine is really tight and I sure could use a few tricks if/when I pull it. There’s never an easy way.

if yours has been in there a long time would recommend getting penetrating oil on the square nuts that are held in inner transom plate and hitting them with some heat

 

[kenny nunez]

If the bolts are rusted in the core of the rear motor mounts and corroded in the inner transom plate you have a real problem.
I have had to use a cutting torch a few times. The area under the bottom of the flywheel housing is where the cut has to be made. Needless to say it gets real nasty by the time the engine is out. One person with the torch and another with a garden hose. Hopefully your bilge is not oiled up causing a fire hazard.
The other option would be to start with a 1/8” drill bit in the center of the bolts working up to a 1/2” bit then pry off the stainless washers. Next with a 1/4” drill bit drill out the rubber around the steel core enough where the engine can be lifted. You then grip the remainder of the bolt with a pipe wrench and work it loose.
Good luck.

 

[1985 Century Mustang]

@1960 Starflite Here's the trick below to removing the rear motor mount bolts. My engine is a 1985 Merc 140 Alpha One Gen One. **Make sure you soak the hell out of the motor mount bolts with a good penetrating oil. Liquid wrench, Kroil, PB Blaster etc.. Keep soaking it every so often as possible...

These were my exact steps on how I actually freed the rear motor mount bolts from the flywheel housing/rear motor mounts.

1. I first cut off the heads of the rear motor mount bolts, and also that spacer below it with a good reciprocating saw (sawzall) and a good blade. *Be careful not to cut into that flywheel housing.
2. I drilled many tiny holes into the bushing with a small drill bit thus chipping out the rubber and some metal in that bushing. I broke a few bits, so be careful. Get as much rubber and metal out of that bushing as possible.
3. I used a MAP gas torch (it's hotter than a regular torch) and burned the remainder of the drilled out bushing.
4. While it was hot, I pried up the whole mount with a pry bar and freed it up, now exposing most of the remainder of the motor mount bolt.
5. I used a pipe wrench, then channel locks to turn the rusted bolt out and bingo it was freed. *Remember there's a nut under the rear transom mount housing you have to get out.

Good Luck, this worked out amazing for me.