Stuck Power Head Merc V-150

[Outrage-19]

I have a 1987 Merc V-150 with a chewed up piston. I have pulled all the wires, hoses, and the 10 bolts the book says to pull but the power head not budge. I have socked all of the bolts in Kriol penetrating oil and heated the lower unit housing from above the bolts all the way to the base of the power head with a propane torch, but it still won’t come off. Using a hoist and lifting eye I lifted the back of the boat off of the trailer (19’ Boston Whaler Outrage) still no go. I did a search in this forum for Stuck Power Head and did not find anything I had not tried. Does any one have any other suggestions on how to get this power head off? Thank in advance for any help.

 

[chumbucket]

Re: Stuck Power Head Merc V-150

Outrage, Is the lower unit off the motor??

 

[Outrage-19]

Re: Stuck Power Head Merc V-150

No

 

[chumbucket]

Re: Stuck Power Head Merc V-150

Could be driveshaft stuck (rusted) in PH holding

 

[jim dozier]

Re: Stuck Power Head Merc V-150

I recently had to remove the powerhead from my Suzuki DT85. Two of the bolts snapped off at the heads despite liberal use of heat and penetrating oil and tapping. The powerhead was stuck because the unthreaded portion of the snapped bolts (about 3 inches long through the engine holder casting) was corroded into the enginge holder casting). Actually one of the bolts was snapped off by some previous mechanic who had tapped the end until it mushroomed. I had to cut off the mushroom with a rotary cutter and start tapping again with a drift to get some movement. The further it moved the more it started to mushroom within the casting until it started to get stuck. I had to tap it back down and drill about 1/4 inch into the end to relieve the stress before it would eventually come loose (it moved ever so slowly, glacial speeds we're talking). You should probably remove the lower unit, that way you'll know that its not stuck on the driveshaft and its easier to stick the driveshaft into a mounted powerhead than to stick a powerhead onto a mounted lower unit.

 

[Outrage-19]

Re: Stuck Power Head Merc V-150

Thanks Chumducket and Jimd. It sounds like the key is patients, persistence, hope for the best, and prepare for the worst. I was planning to replace the water pump any way so I’ll go ahead and pull the lower unit this weekend. Wish me luck.

 

[chumbucket]

Re: Stuck Power Head Merc V-150

Before you get bigger hammer and hotter torch, grab a couple beer's (couple)and stand back survey where you are. I mean on motor

 

[Outrage-19]

Re: Stuck Power Head Merc V-150

Ok Chumbucket I’m always up for couple of beers. I know better than to use a BFH on an aluminum engine. I think I am dealing with the same problem as another member posted on 8/11/02 his problem was that the 4 long bolts at the front of the exhaust housing were corroded in and according to an engineer he was talking to only extreme heat or sawing through the exhaust plate would do it. I don’t want to saw through the exhaust plate so I was leaning toward extreme heat. The other thought I had was if I took a concrete vibrator strap it to the exhaust housing and turned it on maybe it would shake the corrosion free. Anyone else have any ideas?

 

[AndyL]

Re: Stuck Power Head Merc V-150

It won't help but my utmost sympathy is with you. I was the one who was told either acetylene or saw through the exhaust plate. The plate is over $1000 so I gave up. I had considered turning the engine upside down and building a "moat" around the front bolts then properly soaking the bolts with acid and leave to stand. My lower unit was off so it wasn't that holding it on, definetly the long bolts.<br /><br />Please post a notice if you do find the miracle cure.<br />Andy

 

[Outrage-19]

Re: Stuck Power Head Merc V-150

Will do Andy thanks for the sympathy.

 

[jim dozier]

Re: Stuck Power Head Merc V-150

The acid (muriatic like for cleaning pools avaiable at Home Depot) might not be so far-fetched. The trick would be to keep it where it won't hurt something sensitive. I have no experience with it on motors so I take no responsibility for the outcome but the aluminum corrosion is soluble in acid, the problem is that aluminum is also soluble, although less so. I think if you could keep it away from the engine block/powerhead and use small quantities it could help (goggles and gloves). Capillary action would suck up small quantities around the base of the stuck bolts and might loosen the shafts.<br /><br />After I got my powerhead off I was amazed at how tight a fit the stuck bolts were in the holder housing. I had to redrill the corrosion (mostly aluminum hydroxide and aluminum carbonate) with a drill bit to clean the suckers out for the new bolts. It was after that I wondered if acid might help.

 

[Outrage-19]

Re: Stuck Power Head Merc V-150

Thanks Jimd. I think I have both muriatic and battery acid. If I try this approach I will make sure that in addition to the goggles and gloves I have lots of water in case I need to neutralize the acid quick, maybe if I applied it with an eyedropper I could minimize the damage to the exhaust housing. I better plan on a paint job as well with this approach. Does anybody know anything else that neutralizes aluminum oxide?

 

[jim dozier]

Re: Stuck Power Head Merc V-150

Don't use battery acid (sulphuric acid) because it reacts agressively with water. Muriatic acid (hydrochloric acid) is probably better. To be safe you might try diluting the muriatic acid initially with an equal amount of water. If that doesn't work you could try it full strength. You could try less agressive acids like vinegar but they might take a long time and might not work. As I said I've never tried this on a boat, I'm just thinking of the chemistry here. Small quatities carefully placed.<br /><br />Baking soda in water is good to neutralize the OB part when you want to stop the process.

 

[chumbucket]

Re: Stuck Power Head Merc V-150

I have another idea ,but its up to you. Go to www.screamandfly.com About 95%Merc Guru's over there. One more brain might work

 

[badasselectric]

Re: Stuck Power Head Merc V-150

If you do get them out, you might think about a product called noalox made by Ideal. you can get it from an electrical supply house. It is used to make connections with aluminum wire to prevent corrosion. specifically for aluminum. Just a thought it might work better than never seize on aluminum. I know right now you are more concerned with getting it apart than putting it back together.

 

[Tinkerer]

Re: Stuck Power Head Merc V-150

I had to remove corroded bolts and shafts from a tilt bracket recently and no amount of soaking ends with penetrating oils would help. I doubt fluid can get very far in if all the space is already taken up with solid corrosion. I got fluid lower down the shafts by (a) drilling small holes to the side of the shafts and bolts through the alloy casting at an angle to hold fluid as reservoir (refill holes later with cold weld) and (b) drilling down shafts and bolts right beside the casting to get fluid in. Soaked them for a couple of days with plenty of refills with plenty of tapping with a hammer to help things along. Then knocked them out. Only took about two to three hours of careful heavy hitting per two inch section of half inch shaft removed. But I had advantage over you that I could work from both ends of shaft (I'm assuming your bolts are in blind holes) and knock them through. Maybe it would help if you did last bit of drilling on impact drill to vibrate bolt and maybe loosen corrosion a fraction, but I didn't think of it at the time.<br /><br />I used Inox http://www.inox-mx3.com/home.htm which penetrates and dissolves corrosion a lot better than usual penetrating oils (WD 40, RP 7, CRC whatever)which just seem lubricate it if they can get in, then followed it up with those oils because Inox doesn't seem to have much oil in it to assist withdrawal. Maybe Inox or something similar in US.<br /><br />If you want to shock bolt you could hit it with an air hammer rather than concrete vibrator, but check first if it's safe on alloy.<br /><br />Propane torches are useless, assuming U.S. propane is same as useless Aussie propane, as can't get near hot enough. I think I got more heat into a shaft with a blunt drill bit drilling all the way down than the propane ever did - seriously, it came out easiest of the lot and was just as stuck as the rest in the beginning.

 

[Outrage-19]

Re: Stuck Power Head Merc V-150

Ok Jimd nix the battery acid and add baking soda to the water for neutralization.<br /><br />Thanks for the link Chumbucket, I’ll check it out, the more ideas the better.<br /><br />Badasselectric, thanks for the input. I thought I would use lithium grease but I have a friend who is an electrician he probably has some noalox.<br /><br />A friend here at work suggests solder flux might be able to sweat up into the threads with a propane torch it has a mild acid that might cut the aluminum oxide.<br /><br />Tinker, I like your idea of drilling angled holes through the casting and filling them with a solvent, maybe that’s the way to go using inox, solder flux, or penetrating oil with some heat.

 

[Ferrariiwish]

Re: Stuck Power Head Merc V-150

Have you tried leaving in the spark plugs and turn the engine over if the engine is not siezed?<br />This build up of pressure with the head bolts out sometimes helps.Good luck.

 

[Outrage-19]

Re: Stuck Power Head Merc V-150

Thanks for the reply Larry but do you realize we are dealing with a stuck power head not a stuck cylinder head?

 

[Ferrariiwish]

Re: Stuck Power Head Merc V-150

Sorry.<br />Pick it up wrong.<br />Good luck anyway.