1990 Force 120HP motor seized

[marmour]

First I would like to say I am new to this site and it is full of great information. Now the bad news. Went out on Friday and the motor ran fine all day. On Saturday put the and ran for about two hours with no issues. Needed to get gas so pulled to the dock to get the trailer. The motor died. Started the motor back up but each time the boat would die when putting the boat in gear. Used the trolling motor to get on the trailer. Thought maybe we were low on gas and that was the issue. Got gas and put the boat back in the lake. Tried to start the boat and it was very sluggish and wouldn't start. Tried a second time and all I got was a clunk. Thought maybe the battery was drained so pulled out of the lake and hooked the charger up. Battery was fully charged in 30 minutes so not a battery issue. Tried to start again after fully charged and all I got was a clunk again. Came home and thought maybe loose connection or battery terminal. Replaced the terminals and check connections and all were good. Tried to start same clunk sound. The started was engaging the fly wheel but wouldn't turn. Thought the started so I jumped straight to the battery and same clunk. Tried to turn the fly wheel and it would not turn. Motor is seized. Pulled the spark plugs out and when I did the top plug was all rusted as was the spring the the boot. Other three spark plugs looked brand new. Nice and shiny. Checked on the site and it mentioned to pour some oil in the spark plug holes and let set to loosen up the engine. When I did the oil leaked from the carburetor, the bottom on the boat near or out of the water intakes and somewhere about halfway down the length of the engine. My questions are is this normal should the oil leak from some many places? I know I have some issues but does it sound like this motor is repairable and if so at a cost that makes it worth repairing?

 

[pnwboat]

Re: 1990 Force 120HP motor seized

Remove the lower unit before you do anything else. If that fixes your seized motor, then the problem is in the lower unit not the motor. The upper drive shaft bearing in that particular lower unit is very sensitive to low oil level in the lower unit. Not uncommon for the upper bearing to seize up on the drive shaft locking the motor up.

 

[Jiggz]

Re: 1990 Force 120HP motor seized

Since the motor will not turn over, there is no reason to do a compression test at this time. Instead, it is time to open and inspect by removing the head and do an inspection of the cylinders and pistons. From there you should be able to take some pics and then we can take a diagnose if it is worth repairing it or not.

 

[MickLovin]

Re: 1990 Force 120HP motor seized

Of you do the work yourself, yes it is probably worth repairing it, if you get an outboard mechanic to do it, it will probably be very expensive.

 

[marmour]

Re: 1990 Force 120HP motor seized

If it is the lower unit, can that be repaired or does it require a new lower unit? What would be the cost for those options?

 

[pnwboat]

Re: 1990 Force 120HP motor seized

Depends on exactly which lower unit you have. Typical cost for the upper bearing assy is around $50 - $70. Seal kit for the lower unit in the neighborhood of $75. Unfortunately the lower unit has to be disassembled because that bearing is pressed onto the drive shaft and requires a hydraulic press to remove the old one and install the new one.

A complete used lower unit is an easier option if it is in fact locked up. Look around in the local used marine parts auction sites. I can usually find them for $300 or less, but you might have to put in a seal kit and or a water pump impeller.