1989 US Marine Force 50 Need some help on a few issues.

[Aedin123]

First off I would like to thank everyone who posts to this forum. I have gotten so much help over the years and saved a boatload (pun intended ) of cash.

I have searched but come up empty on these topics.

About Me: I am an amateur at outboard repair but have been doing basic maintenance (changing lower unit oil, fuel filters, water pumps ect on my various outboards for a number of years. With the proper guidance (manuals or forums) I think I can handle most items of business on a motor.

I recently purchased a 1989 Sun Chaser Bass Buggy pontoon and it has a US Marine Power 50HP with a model number of 507F9B Serial of 1252

First Issue:

For the life of me I cannot find a repair manual for this motor. Can someone point me in the right direction? I would prefer a good old fashioned paper manual but if I have to settle for an E-version I will.

Secondly:
This question probably pertains to someone who actually owns this motor or has worked on one. I need to remove the old starter as it needs a rebuild (bad brushes I think) The starter that is in the motor currently is clearly a replacement as it is too short to be bolted into the original bracket and is simply attached by the two bolts that come up thru the top of the bracket. Even tho it is shorter than the original would be, I still cannot seem to get it out of the bracket and free from the motor. There just isn't enough space. Will I need to somehow drop the lower motor housing to get it out? If so could someone kindly explain the process of doing so?

Lastly:
I believe (feel free to correct me if I am wrong) that the compression exhaust holes are plugged. I came to this conclusion because the motor is very difficult and jerky to try a manual pull start when attaching a rope to the flywheel. If i pop out the plugs it is no issue at all. When i put the plugs back in the motor, the problem returns. Could someone tell me the location of the relief holes and the process to get to them and a good way to clean them?


Thanks ALOT!

Aedin

 

[Jiggz]

No Title

First question - I am not aware of a specific repair manual for your Force 50 HP. What I use is a Clymer Force Outboard Shop Manual which generically covers all 4~150HP from '84-99. You can find it here at Iboats where I bought mine.

Second Question - The starter has two mounting bolts on the top and there should be another bolt for the bracket at the bottom which is also attached to the engine block. See drawing item 7. Usually, to dismount the starter just remove the bottom bolt first and the bolt from the engine bracket to remove the bracket. And then remove the two top mounting bolts. With a little tap the starter should drop vertically. Just make sure the cable connection is also disconnected.

Third Question - There are no so called exhaust plugs on this motor. If the motor is hard to crank or turn over manually the first step is to drop the lower unit. Then try again, If it is still very hard to turn over (with plugs on) the next step is to do a compression check. If compression readings are low ( norm is 90~150 PSI with plugs removed) remove the head and do internal inspection of the cylinders. If you cannot perform compression checks due inability to turn over the motor either with starter or with a rope, then you have no choice but to remove the head and inspect. Try to save the head gasket as much as possible.

 

[jerryjerry05]

As far as finding the manual GOOGLE!!!
"50 hp force outboard manual" 41 different manuals for sale.
From the serial# it's a 87 or 89
Follow Jiggz suggestion on the compression test.
Make sure the battery is good and hot.

And pictures always help identify the motor.

Usually the 50 is a great little motor.
And if taken care of it will last a long time.

 

[Aedin123]

First question - I am not aware of a specific repair manual for your Force 50 HP. What I use is a Clymer Force Outboard Shop Manual which generically covers all 4~150HP from '84-99. You can find it here at Iboats where I bought mine.

Second Question - The starter has two mounting bolts on the top and there should be another bolt for the bracket at the bottom which is also attached to the engine block. See drawing item 7. Usually, to dismount the starter just remove the bottom bolt first and the bolt from the engine bracket to remove the bracket. And then remove the two top mounting bolts. With a little tap the starter should drop vertically. Just make sure the cable connection is also disconnected.

Third Question - There are no so called exhaust plugs on this motor. If the motor is hard to crank or turn over manually the first step is to drop the lower unit. Then try again, If it is still very hard to turn over (with plugs on) the next step is to do a compression check. If compression readings are low ( norm is 90~150 PSI with plugs removed) remove the head and do internal inspection of the cylinders. If you cannot perform compression checks due inability to turn over the motor either with starter or with a rope, then you have no choice but to remove the head and inspect. Try to save the head gasket as much as possible.

Thanks to you both! I had previously purchased the seloc version and found it to be highly lacking in specifics, especially relating to my model. I have ordered the Clymer version and hope that is a better source for me.

I was able to get the starter out using Jiggz information and it is now at the rebuild shop. I will get it reinstalled Friday and complete the compression tests listed. If I have issues still I will shoot some pics and maybe make some videos to illustrate better.

Thanks again!