Novice attempting to tear down 1988 125 hp Force

[kru45]

Two years ago engine failed after running wide open for a period of time. Boat used a couple times of year the preceding four years with little to no maintenance done in those years. Bought the boat new in ?88, Bayliner Cobra. Had several repairs through the years, piston, trim, impeller a couple times.
Figured piston or cylinder due to a lean condition or improper cooling based on previous experience. Compression test done two years ago showed low compression in cylinder no.3. Finally looking to fix but don?t want a repair bill that is larger than what the boat is worth.

Pulled the head, cylinder 3 (2nd from top) has some minor scoring but piston looks in good shape. Cylinder 4 looks to have a small groove also, again piston in good shape.
Wanted to tear down and deliver to a shop to repair hole 3 and 4 and have them replace pistons and rings, assume have to get oversized piston and rings. Have the electrical pulled away from power head, carbs removed and bolts holding the intake side of housing. Can?t seem to get the housing to come off. Still have flywheel attached. In over my head?

 

[tater76]

Re: Novice attempting to tear down 1988 125 hp Force

Is the powerhead off the leg and base plate? You need to pull the powerhead to do what you are trying to accomplish. Unfortunately, it is a bit of a chore but doable with basic hand tools. Do you have a manual?

On the other hand, if you think that the scoring could be honed out you might save some money and do it yourself. You can pull the pistons without breaking the case in half through the reed openings. Pull the endcaps off the rods and slide them out, hone, re-ring, clean, install, and reassemble. Yes it is more labor intensive than that, but will save you dough if you don't need to rebore.

 

[jerryjerry05]

Re: Novice attempting to tear down 1988 125 hp Force

Profile? You might be close to some one who can help.
The flywheel needs to come off.The timer/trigger needs to come off then the case's will seperate after you remove it from the base.
Don't half step if you wan't a dependable motor.
When I rebuild I take it down all the way.That way you can inspect EVERYTHING.
You never really know why it went bad in the first place so a good inspection is necessary.

 

[kru45]

Re: Novice attempting to tear down 1988 125 hp Force

Tater: went on-line and bought Seloc subscription. Less than impressed. would prefer to have diagrams of my engine!!! I see and read about what you what you suggest about going throught the reed openings.

More in line to pulling the power head and having someone go thru it. By doing so wouldn't I have the rings replaced on 1 and 2 also?

 

[tater76]

Re: Novice attempting to tear down 1988 125 hp Force

Yes, if you send it to a shop for a rebuild they will replace rings on all four. If it were me, and the cylinders were within honing range, I would pull all 4 via reed openings, order new rings for all, hone all 4 cylinders, and reinstall. However, if the cylinders are pretty rough, or out of spec you may be looking at reboring the bad one or ones and buying oversized pistons. A shop can do that.

And Jerry is right, if you are going to go to the effort, you may as well split the case so you know what you are sending to the shop. This way you know what you need to replace, and you can get an idea of how everything works.

When you said low compression, how low is low? I worked on a 50hp force that had 130 on the lower piston, and 100 on the top. I pulled the top piston to find stuck rings, and light scoring in the cylinder. I honed the cylinder, and cleaned the rings so they functioned again, and the compression went up to 128.

 

[bentle]

Re: Novice attempting to tear down 1988 125 hp Force

When you said #3 (second down from top) that caught my attention because on my 125force
outboard it goes #1#2#3#4 starting from top down. Could the sparkplug wires have been in the wrong order from the start of your motor prob. or did I misunderstand what you was trying
to say?

 

[kru45]

Re: Novice attempting to tear down 1988 125 hp Force

After giving up four months ago, I'm at it again. Want to pull powerhead, but can't get the flywheel off. Have a tripod type puller and have popped to chunks out of the flywheel. Not good I assume. Any good/better ideas to remove the flywheel? Again this is an 1988 125 Hp Force.

Thanks
Kru45

Yes, if you send it to a shop for a rebuild they will replace rings on all four. If it were me, and the cylinders were within honing range, I would pull all 4 via reed openings, order new rings for all, hone all 4 cylinders, and reinstall. However, if the cylinders are pretty rough, or out of spec you may be looking at reboring the bad one or ones and buying oversized pistons. A shop can do that.

And Jerry is right, if you are going to go to the effort, you may as well split the case so you know what you are sending to the shop. This way you know what you need to replace, and you can get an idea of how everything works.

When you said low compression, how low is low? I worked on a 50hp force that had 130 on the lower piston, and 100 on the top. I pulled the top piston to find stuck rings, and light scoring in the cylinder. I honed the cylinder, and cleaned the rings so they functioned again, and the compression went up to 128.

 

[Justinde]

Re: Novice attempting to tear down 1988 125 hp Force

Depends on the chunks- a damaged flywheel should be replaced. As for removal, your puller and a light tap should have done the job- I am assumiong you removed the bolt?

Keep at it, some of the guys may have some tips as to removal that are more enlightening than mine. I have a 1988 125hp, and love it. Its relaible and easy to work on.

Best of luck!

 

[stubtail]

Re: Novice attempting to tear down 1988 125 hp Force

To pull the flywheel, even though it may be scrap, there are (or hopefully should be) three 1/4-20 tapped holes near the center of the flywheel. Using a harmonic balancer type puller, the three bolts are inserted through the slots in the puller plate and threaded into the flywheel. You may need to procure grade 5 or better bolts, and with a little heat from a heat gun, you should be in business.

 

[redstrat]

Re: Novice attempting to tear down 1988 125 hp Force

I have found that you can place a tapered bar between the flywheel and the exhaust housing. Back the flywheel nut to the end of the crank shaft. pry up on the flywheel while tapping on the (nut) end of the crank. Rotate the flywheel every few taps. I've had good success with this method. I bought a Force shop manual on ebay for 25 bucks, well worth it. Good luck

 

[tater76]

Re: Novice attempting to tear down 1988 125 hp Force

There are lots of methods out there, but you really should invest in a steering wheel/harmonic balancer puller. There should be theaded holes in the top of the flywheel just for this. Usually if you install the puller and get some good pressure on it, then tap the puller end with a hammer it will pop. Sometimes a good soak overnight in PB Blaster will help. If you have access to an impact gun, use it on the puller. The vibration and smacking of it usually do the trick.

 

[Frank Acampora]

Re: Novice attempting to tear down 1988 125 hp Force

Any reputable machine shop will not bore an engine with the crank in it. SO: to remove the powerhead, remove the rear shroud--six bolts outside and six more inside the lower cowling. Now remove the six nylock nuts from the perimeter of the midleg flange. Up top and inside the engine cowling remove the six 3/8 (9/16 head bolts holding the match plate and exhaust tube--dont worry, you will see it later. Disconnect the shift linkage rod UUsually 1/2 or 9/16 nut) from underneath the lower carb. Remove the rest of the bolts holding the lower cowling to the engine because you need the room to pry.

Now, there are several pry points on the match plate and you must use a large crowbar and a couple of really big screwdrivers to pry up the engine. The six studs may be corroded into the midleg flange and this is the most difficult part of removing the engine.

Once you have the block off the leg---two people or a lift, it weighs a little more than 100 pounds--now you must remove the match plate from the block. Undeneath it are four nylock nuts. remove them and pry the match plate off.

Hopefully you have first removed the flywheel, stator, and trigger. Now remove the stator mount (five screws, usually allen head).

NOW after driving out the two diagonally placed locating pins and assuming you did not miss any case bolts, you can use the pry grooves and split the crankcase.

Note: There are two bolts behind the case at the top: One behind the starter mount and the other on the other side. The two fillister slotted head bolts at the bottl also hold it and must be removed.