1990 Force 90 Won't Crank -Binding

[Derrick Fronckowiak]

Fellow Force Owners-I was running my 1990 Force 90 on the muffs and shut it down (nothing unusual). Later on (after a few hours) I went to start it again and the starter would engage, but would bare rotate the flywheel and then, it wouldn't rotate it at all. I had just gotten a new battery and had good voltage. So I thought the starter was dying, so pulled the plugs and tried again-no different than before I pulled the plugs. Put a socket and breaker bar on the flywheel nut and felt it binding. Could barely rotate the flywheel and had to jiggle it counter-clockwise and then clockwise just to get a little rotation. I pulled off the carbs manifold/reed plates, took my cheap Chinese endoscope and looked into each chamber for some kind of mechanical failure or breakage/blockage (looked in the cylinders as well), but couldn't find anything. Could my interior trigger flywheel magnets be coming apart and binding? Could my crankshaft had sheared between the journals or somewhere else? I'd really like to know what's causing this before I yank off the powerhead and split the case (which I may end up having to do anyway). Figured I'd ask this forum (this great storehouse of knowledge and experience), before I do something stupid(er). Anyone have any ideas or experience this before?

 

[racerone]

How did this motor run for you last season ?-----Remove lower unit and see if it turns easier.

 

[Redbarron%%]

Try turning it with the plugs removed.

 

[The Force power]

After you dropped the LU as Raceone suggested & no change; pull the head to see if the cylinder-walls are scored??
Possible broken ring(s) stuck in the exhaust-ports
The '90 does not have glued magnets on the fly-wheel it is a solid band

 

[jerryjerry05]

Try turning it with the plugs removed.

He said he did with no difference.

You pull the lower yet?

 

[Jiggz]

As mentioned, drop the LU first. And then try again. If it is still binding then remove the head and do an inspection of the cylinders and pistons.

 

[Derrick Fronckowiak]

He said he did with no difference.

You pull the lower yet?

JerryJerry05, Jiggz & Racerone,
You guys called it right! I dropped the lower unit and the motor rotates just fine! Further investigation into the lower unit revealed that the lower drive shaft was binding. The upper bearing was trashed (it has some melted pieces of the bearing cage globbed onto the bearing race)! And almost all of the lube in the lower unit was gone and of course there was some water in there as well. So the bearing failure was a symptom/result of the fluid that leaked out of the lower unit (they tend to run better when they're lubed-sarcasm). Any areas that you guys know of that typically have the seals leak on the lower unit? I'm going to replace all seals, but I want to be sure that there isn't something wrong with the housing itself. Haven't seen anything obvious (like cracks in the housing), but if there are specific areas that are prone to leaking, that would be helpful to know too.

 

[racerone]

Take the lower unit apart.-----Inspect all pieces .----Inspect housings that hold / locate bearings.----Price parts / availability.------Perhaps start a search for a used lower unit.

 

[Derrick Fronckowiak]

Take the lower unit apart.-----Inspect all pieces .----Inspect housings that hold / locate bearings.----Price parts / availability.------Perhaps start a search for a used lower unit.

Yep, That's what I'm doing. Right now I estimate about $300 in parts. Prop shaft and bearings are in pretty good shape. Replacing all seals, pump, both bearing sets for the lower drive shaft and retainers (I trashed the retainers during disassembly because I didn't have the spanners to properly remove them, but I'm getting the right tools for reassembly). I really don't want to have to get another lower unit. Can't imagine what someone would charge for one.

 

[Nordin]

My experience from these LU is that you have to be really sure you have gear oil all way up to the upper bearing.
The two holes in the upper part has to weep out gear oil when filling it.
Check out the OEM factory manual how to fill the LU with gear oil.
As the upper bearing is a tapered roller bearing it is more sensitive from lack of oil.
To replace the upper bearing the OEM factory manual calls for matching gear case and matching piniong gear and bearing.
The lash/back lash for the piniong to forward/reverse gear was computer calculated but I have done this without this just by measure the lash and shim it by experience from Chrysler one piece LU shimming values and it has worked out good.

Those late 80:es and early 90:es LU had different solution of seals for the shift shaft. The one with a rubber bellow for the shift shaft was a bad design and the bellow fail after a while.
Now this bellow is N/A.
If you have the bellow style seal check it out for leakage.
I know Franz Marine had an new solution to replace the bellow seal but it was expensive.
It was a new style top cover for the LU with regular style seal for the shift shaft.
I do not know if he has some of these left and it was some kind of R/R for this cover.
Otherwise these LU do not leak at any special places, just check all other seals and o-rings and pressure test it before you put it back.

 

[The Force power]

Those late 80:es and early 90:es LU had different solution of seals for the shift shaft. The one with a rubber bellow for the shift shaft was a bad design and the bellow fail after a while.
Check if its made out of metal or plastic (metal=old style)
Plastic = you're ok & get the replacement seal for