lower unit mounting bolt stuck and stripped, help!!

[f4igrad]

i am trying to remove my lower unit to replace the clutch dog, and one of the four bolts that holds the lower unit in place is completely stripped. the bolt is totally frozen in place, so i have no clue how I am going to get it off. there is a fin under the bolt, so I can't even get a bolt extractor on it, only a wrench will fit on the head.

it seems like this type of stuff always happens to me when i try to work on things, it is extremely frustrating.

 

[red boat]

Re: lower unit mounting bolt stuck and stripped, help!!

You should be able to get a pair of vicegrips on the head and get a propane torch and heat the area that the bolt threads into and it should come out. just make sure you replace the upper bearing carrier o-ring and seals because the heat will destroy it and also the water pump.

 

[f4igrad]

Re: lower unit mounting bolt stuck and stripped, help!!

how long should i heat the area for?

 

[f4igrad]

Re: lower unit mounting bolt stuck and stripped, help!!

ok, i have heated the area over and over again, and the vise grips are just stripping the bolt head even more. small pieces of the bolt head are just being rounded off like smooth glass.

any other ideas?

 

[ezeke]

Re: lower unit mounting bolt stuck and stripped, help!!

Can you cut the head off with a dremel, or drill in far enough to cut the head off?

There will be enough of a stub left to get a vice grip on once you have removed the gearcase. A lot of the time the corrosion that is really locking those bolts is not in the threaded section.

 

[f4igrad]

Re: lower unit mounting bolt stuck and stripped, help!!

ok, i cut off the head with a dremel, but now i can't get the lower unit off. it wiggles back and forth, but it won't drop down. i definitely got all of the bolts, and i unscrewed the shift shaft behind the starter at the top of the engine. any tricks to getting the lower unit off?

 

[ezeke]

Re: lower unit mounting bolt stuck and stripped, help!!

What motor is it?

 

[f4igrad]

Re: lower unit mounting bolt stuck and stripped, help!!

1973 evinrude 50 hp. i am afraid something really bad has happened...i try to twist it off and it just rotates around where that last bolt is stuck...i can hear the bolt twisting in there. i am afraid that the threads of the bolt extend into the lower unit, so cutting the head off the bolt has done nothing more than make it impossible for the lower unit to be removed.

 

[ezeke]

Re: lower unit mounting bolt stuck and stripped, help!!

They are not made that way. The bolt is smooth as it goes through there and so is the hole. That is corrosion.

Get some shims from a building materials place and bring the unit down together maintaining an even distance on the mating surfaces. You have too many parts in the way to do any good by twisting.

 

[f4igrad]

Re: lower unit mounting bolt stuck and stripped, help!!

the problem is, there is hardly any gap at all on the side where the bolt is. i am not sure how i will hammer a shim in there. i tried using a flat blade screwdriver, but it just started bending the metal of the lower unit.

 

[ezeke]

Re: lower unit mounting bolt stuck and stripped, help!!

Get an old bolt and see if you can free it by tapping the stub of the bolt. I thought that the heat you applied would have made it looser, but apparently it did not.

 

[rickdb1boat]

Re: lower unit mounting bolt stuck and stripped, help!!

Shoot some penetrating oil up in there too. Something like PB Blaster will help...Don't get impatient. This happens more often than you think. Don't pry on it with screwdrivers and the like. Get the wedges and let them do the work. It may take some time before it breaks loose..

 

[imported_lorin]

Re: lower unit mounting bolt stuck and stripped, help!!

Try more heat and using penetrating oil. Heat-oil, heat-oil, heat-oil,-get the picture? Do not dismay-worse things have happened to 90% of the people reading this including myself (I once stripped out the adjustment screw for the ignition points on my VW van while in a canyon in Death Valley-that should make you feel better). It will eventually come free using all the strategies that have been suggested.

 

[f4igrad]

Re: lower unit mounting bolt stuck and stripped, help!!

i tried hammering the wedges, but they just break as soon as they get started. these are the thinnest wedges that they sell. i don't know how the penetrating oil is going to help, i can't spray it on top, and if i spray the bottom of the bolt then it just runs right back out....there is no way it is going to make it up to the corrosion.

 

[f4igrad]

Re: lower unit mounting bolt stuck and stripped, help!!

i give up. i have been working on this stupid @ss thing for 9 straight hours. i was thinking that today, i would have the clutch dog and forward gear replaced, as well as the impeller. instead, i can't even get the lower unit off after 9 hours of working on it. i have sprayed an entire can of PB on it, used an entire cylinder of propane, and hammered 15 wedges into it, but it will not budge. i even used an air hammer on the bolt to try to break the corrosion free. now my boat is worthless. at least before we could put around and go swimming, now the whole engine is a pile of junk.

 

[rickdb1boat]

Re: lower unit mounting bolt stuck and stripped, help!!

Hammer the wedges in there as tight as you can get them and let it sit overnight. Then tighten them up again tomorrow...And continue to do this until it falls..It may be that the driveshaft is frozen in the powerhead..Give it time...

 

[f4igrad]

Re: lower unit mounting bolt stuck and stripped, help!!

i can only hammer the wedges in on one side, the side that the bolt isn't frozen. the side that has the bolt on it is so tight that there is no way to fit a wedge in there. should i just keep hammering them in on the right side.

i talked to the guy i bought the engine from, he works on these for a hobby. he said he will help me with it on saturday for a fee. the only thing is that it is 150 miles, one way, to his house. if i can't get it to drop by saturday, i guess i will tow the boat down there to work on.

 

[RPJS]

Re: lower unit mounting bolt stuck and stripped, help!!

Are you 100% sure you have got all of the head of the bolt off, just a small burr would be enough to hold the LU on the bolt.
Don't lose your cool with the job or you will end up doing some damage, the LU will come off it's just a case of taking things slow.
Plenty of heat,oil & paitiance, heat it up, get your wedges in as far as they will go then spray some oil into the gap between the LU and leg (even if the gap is only very slight the oil will find it's way to the bolt) then leave it to soak for a few hours and start over again with the heat.

 

[Walker]

Re: lower unit mounting bolt stuck and stripped, help!!

What you probably have is bi-metal corrosion on the bolt shaft and the aluminum case it goes through. Happens all the time. Advice on getting it loose. Persistance and some carefull persuasion. A hammer and a 2x4 come in handy but don't break any of the lower unit.

 

[rickdb1boat]

Re: lower unit mounting bolt stuck and stripped, help!!

one of the four bolts that holds the lower unit in place is completely stripped.

I gotta ask. Are you absolutely sure you have all the bolts off? Did you get the one under the fin? There are more than 4....