Johnson 150 V6 Powerhead Stuck

[sailnaked6842]

Hey guys, been reading your threads a lot and they've been a wealth of information for helping me take apart my motor. But currently the motor is almost all the way apart, ready to take to a machine shop to remove some stuck bolts and hone/bore the cylinders...except the powerhead is stuck. Really stuck. My father and I attempted to remove the powerhead this morning and removed (or at least broke the heads off) the bolts holding it on. I believe there were 3 on both sides, 2 studs with nuts in the front, 2 bolts in the front, and 2 studs with nuts in the rear. After removing all the bolts, we positioned the engine under a lift and no matter how hard we tried could not get the motor off the base. Definitely in the realm of ~5-600 lb-force, but it wouldn't break free. Is there anything I'm missing? Heard a little about a shift linkage but my Seloc manual says nothing about needing to remove that. Is it possible the drive shaft froze to the crank? I can post pictures too if that will help.

 

[TD_Maker]

Re: Johnson 150 V6 Powerhead Stuck

I would drop the lower unit just to be sure that is not what is holding it on. Indeed the drive shaft could be frozen inside the powerhead.
Now you will have to disconnect the shift linkage you spoke about.

 

[Bosunsmate]

Re: Johnson 150 V6 Powerhead Stuck

Do as above, drop LU and disconnect shift shaft linkage, its under the bottom carb.

Did you remove the bolts or have you left the bolts there with no heads?
Those bolts normally seize in the exhaust adaptor housing which is what they go up through and into the base of the motor.
Getting these removed can be a real curse.
Ive had to drill them sideways out and then epoxy the hole back in later.
If they are still there you hopefully might be able to get some heat on to them and give them a good whack to try and break up the corrosion holding them in. Also heat the housing up, but be careful you dont melt it.
Ive done the above and managed to get some plumbing pliers/vice grips on them and turn them out.
Back them down then up then down, as if you just back them out the threads can get full and it will re stick again.

Is it a salty?

 

[Bosunsmate]

Re: Johnson 150 V6 Powerhead Stuck

Once you lift it off the bolts with no heads should undo easily, well they have in 40 year old satlies ive worked on.
I backed out these bolts every few years and anti seize compound then so i dont have to do it again.
Often ive rebuilt a motor and lifting the powerhead off has taken over 2/3 of the whole rebuild time.

Trying not to freak you out but lots of people here have being through it themselves, so perservere

 

[sailnaked6842]

Re: Johnson 150 V6 Powerhead Stuck

Thanks for the replies, guys. I believe the shift linkage has been removed from the motor, but hasn't been pulled out of the lower unit. For the record the bolts that the heads popped off originally rounded off, were then ground off and then cold chiseled once the grinder would not reach. I'm worried those are corroded in there to the point they're not letting go. Would heat and tapping be the way to go, or there better methods? Secondly, since the lower unit is on, what would removing it help with? I've heard it helps but none of the manuals say what it will help with?

Sadly yes, it's a salty.

 

[sailnaked6842]

Re: Johnson 150 V6 Powerhead Stuck

Also I can get pictures if that would help

 

[Bosunsmate]

Re: Johnson 150 V6 Powerhead Stuck

Removing the LU means you can rule out the driveshaft seizing in there and holding the powerhead down

 

[boobie]

Re: Johnson 150 V6 Powerhead Stuck

As said above, try the lower unit next.

 

[TD_Maker]

Re: Johnson 150 V6 Powerhead Stuck

Thanks Boobie.