Cracked gearcase - ~91 90hp Force

[interalian]

The saga of my neighbor's dad's boat continues. Went to change the leg oil (was empty) and started with a pressure test. Air coming out of the propshaft seal, and a nice crack in the gearcase. Ii suppose this gearcase is totally toast as the driveshaft turns with a nasty squawk/grind/clunk sound. Must have been full of water, froze and rusted.

I'm in Southern Alberta - anybody know a place for used Force bits? Motor is 906X91C - anybody know what years this would cross to? I'm not against the idea of buying a whole motor for parts.

http://smg.photobucket.com/user/inte...e8hwq.jpg.html

 

[Nordin]

Interalian .....If you engine is a 91 year model it suppose to have a two piece driveshft and a dual exhaust LU.
You should look for a LU from 90-94, maybe a 89 LU will fit.
Also check if you have a 20 in or 25 in leg.

Some information: Before 1989 Force 85-125Hp had a one piece driveshaft LU with single exhaust.
In 1989 or 1990 they changed to a two piece case with dual exhaust and in 1995 or maybe late 1994 (i am not sure) they changed over to Mercury LU.


I am in Sweden Europe and do not knowplaces for used LU, but I will sugest you to check Ebay and Craige list.
Franz Marine, Maxrules may have restored units BUT they will cost you a fortune.

 

[jerryjerry05]

Post a pic of the whole lower unit.
​The one piece drive shafts, some will fit your motor?
906X91C ​ seems this one used Mercury gears??

Changing motors can be fairly easy or a real pain.
​The older ones up to 92 should just bolt on.
The newer needs transom repair and new holes.

 

[interalian]

No Title

Thanks guys. This motor and boat will be on the block once it's running, so the idea is to get it going for as little dough as possible, as quickly as possible. Market for used boats around here evaporates quickly as summers are so short.

Yes, it's a two-piece driveshaft and has the large exhaust nozzle plus thru-hub. I've checked our local sale site but nothing is coming up. Owner is checking around at shops in case anybody has a junk pile or a used one. Fingers crossed.

I was thinking on the line of a used motor as getting one with the same LU that maybe has a blown powerhead, buying the whole thing, taking the LU and scrapping/selling the rest. Pipe dream...

 

[interalian]

No Title

So, found this 400 miles away for $1000 used, tested, shipped and 90 day guarantee.

I suppose a running boat is worth a lot more than one with a borked motor.

 

[Nordin]

Okey, is 1000 dollars for a complete engine or just the LU?
Yes, there is a 90 days guarantee.....that is good.
BUT 1000 dollars for a LU ?????
Well OB LU are not cheap.

I would search a little more at Ebay and Craiglist.

 

[interalian]

Sadly it's the going price. Acually on the low side of the 4 prices I got. Hope we can get it sold this year and recoup the cost.

 

[interalian]

Funny add-on: when I took the LU off, I thought it was odd that the shift shaft seal was sitting above the water pump plate instead of being pressed in. Must have been a lot of water in there and when it froze it pushed the seal out of its hole as well as cracking it down by the drain plug.

New rules for troubleshooting boats: observe, observe, observe. When you're told "it was running fine last time we had it out", it's meaningless.

 

[Nordin]

Something I tell everybody that ask me about what to do with the OB for winter or season maintain.
Change the LU oil. Check/change it every autumn. It is woth every dollar and the most imported thing to do.

 

[jerryjerry05]

It "might" have been running??
Poorly and did they say it moved?

 

[interalian]

Jerry, it moved. (Seinfeld reference.)

We actually had this rig running for 15 minutes on our local lake, BEFORE doing any repairs. (!)

You saw my other thread here about this motor. Blown out bypass gasket on middle cylinder. Starts in gear. Shredded water pump. Exploded thermostat. This motor was a basket case that suffered much from lack of simple MAINTENANCE. Now that they've commited to replacing the LU, it'll sell, but the profit will be far less than had they maintained it.

And yes, changing the LU oil is critical. That $7 bottle will save you big bucks in the end.



BTW, all the fearmongering about unthreading the shift rod from the clevis down low is just that: fearmongering. I took the lower waterpump plate off to see just how hard it could be, and removal and installation is a snap. The block it threads into pivots and you need to rotate it to thread the rod in - easy. Not a lot of 'adjustment' range, so look elsewhere for that (under the carbies).

 

[jerryjerry05]

I think the thing with the lower unit is the pivot pin on the side of the lower unit.
If it's been removed? then it can be a pain to reinstall.
​Usually they remove the pin and then spin the prop or driveshaft and things move and it needs to be taken apart to fix.
And the same with the shift rod.
If it's unscrewed and then something moves?? PITA
​The shift rod is just that, no adjustments there.

 

[interalian]

Yes, removing the pivot pin on the nose of the case would be a fatal error for sure.

Hey, I have to swap out the lower motor mount. I suppose the only way to do that is to lift the powerhead a bit? I've already got the leg back cover off which exposes the limit straps on the side of the exhaust housing, and the front plate is off. No way to access the mount bolts to the exhaust housing though. The upper mount bolts are visible as well. If it's too hard I may just button it back up the way it was...

 

[interalian]

No Title

I've pulled the carbs and silencer to help access parts for what I'm fixing and have found the elbow fitting at the bottom of the silencer is missing.

According to one site, the descriptions for 18 and 21 are:

18 - elbow

21 - fitting, drain with metering cup.

So I'm going to go out on a limb and assume that if I found a suitable "elbow" to connect the hose (20) I'd be set to go. Thoughts?

 

[jerryjerry05]

Any thing you get will be better than what you have.

 

[interalian]

No Title

Absolutely true. If the motor is tuned to run with a metered 'leak', the hose should have been left open rather than plugged.

Hey, I have to swap out the lower motor mount. I suppose the only way to do that is to lift the powerhead a bit? I've already got the leg back cover off which exposes the limit straps on the side of the exhaust housing, and the front plate is off. No way to access the mount bolts to the exhaust housing though. The upper mount bolts are visible as well. If it's too hard I may just button it back up the way it was...

Getting ready to do the mounts. Rigged this up to take the weight of the powerhead while the upper mounts are loose.

 

[interalian]

No Title

Didn't need to hoist it to get the mount removed. Just had to take off the carbs, unbolt the upper mounts and tilt and block the powerhead like so.

While it was tilted like that, half a dozen bolts fell out of the housing. Some very sloppy work by prior techs.

 

[interalian]

New mount in place. New leg on, complete with new water pump assy (can't believe how dinky the pump is compared to my 'rude). Time to set the shift height. Then it's carbies and lake test.

 

[jerryjerry05]

Set the shift height??
Shouldn't need much if anything on setting the height??
You might need to adjust the cable end if anything??

 

[interalian]

This motor used to start in gear and could not be adjusted properly within range on the shift cable's adjustment. I'm hopeful the old LU was the problem, but have expected the possibility I'll need to adjust the linkage under the intake. Since the carbies had to come off in order to tip the motor forward to swap the lower mount, it's a no-brainer to make sure the shift is set right before they go back on.

Judging by all the other maintenance issues on this motor, cleaning the carbies makes sense. One of the mounting nuts on the bottom carb was backed out fully, doubt it was ever tightened from the last repair.