Force 120 with low compression seeking advice

[submariner1980]

Re: Force 120 with low compression seeking advice

The forum is eager to find out what else you have inside the motor??????

 

[jerryjerry05]

Re: Force 120 with low compression seeking advice

No need to cover anything.
The good thing about outboards is they are pretty much waterproof
Unless they are completly under

 

[jdamron]

Re: Force 120 with low compression seeking advice

Thanks again everyone for the replies. I have not done a whole lot the last couple of days due to the holiday, but I did work on it a little today. I was able to remove the spacer/adapter plate from the bottom - see first picture below. A couple of the heads of the allen screws were pretty swollen with rust and should probably be replaced but otherwise it came off pretty easily.

So I am now trying to remove the flywheel nut. In my manual they say to use a special part (91-52344) to keep the flywheel still while loosening that flywheel nut. I was wondering if anyone had any suggestions on an alternative. I tried to jam a pry bar against a bar positioned into the starter motor bracket as seen in second picture below but this is not working very well. I can't seem to get enough force on the nut without the pry bar slipping and the flywheel spinning.

 

[Jiggz]

Re: Force 120 with low compression seeking advice

Oh no, not that way to remove the flywheel nut. You'd be better off soaking it in WD-40 and then using an impact wrench. Use those three eyebolts you used earlier, although you only need two, and the breaker bar handle to steady the flywheel. If you do not have an impact wrench, you'd be better off borrowing or renting one.

 

[Jiggz]

Re: Force 120 with low compression seeking advice

Here's another trick used by forum members which is simple yet effective.

http://forums.iboats.com/force-chrysler-outboards/hey-tater-615690.html

 

[jdamron]

Re: Force 120 with low compression seeking advice

Hello everyone. I really have not forgotten about this project I have just been so busy lately with family and the holidays that I went a long time without being able to do any work on it. But I finally got some tools from Harbor Freight the other day and made some progress. I got an impact wrench as recommended above and was able to finally loosen the flywheel nut. Even after initially loosening it I could only get it a few threads loose and had to go in and out with it over a couple of days while spraying it with penetrating oil until finally it came all the way off. And then I used a large 3 jaw puller as recommended in another thread I found on this forum and was able to remove the flywheel. See picture below for reference. Next I will work on removing the stator and hopefully I can work on that and the next steps some this weekend. Thanks again everyone for the helpful advice.

 

[Jiggz]

Re: Force 120 with low compression seeking advice

Looking good and you are obviously making progress. With digital cameras around everywhere, make sure you take a lot of photos every step of the way for reference on putting it back together.

 

[jdamron]

Re: Force 120 with low compression seeking advice

Well after getting that flywheel removed the rest of the disassemble when surprisingly fast. Even with labeling everything and taking my time today it went much faster than I imagined and I really enjoyed using the air compressor impact wrench. So now I have it all apart.

The good news is I can now tell for sure why the engine was so hard to turn and I know the source of the strange object I was seeing through cylinder #1 a few weeks ago. One of the roller bearing cages around the crankshaft went completely out and the plastic cage that holds the bearings melted and that is what I was seeing. And the bearings are all mashed up. I am not real sure why the compression in #1 was low but maybe some of that melted material was making the piston #1 not seat very well.

So now my big question is if this can be fixed. I am assuming I can get a new roller bearing assembly for the crankshaft but what I am worried about are two things. 1) Where the roller bearings go over the crankshaft is a bit pitted and not very smooth any more - can a machine shop smooth that out or does that not matter too much? and 2) there is some sort of pin/dimple in the crankshaft cover that holds the bearing cage in place and that pin/dimple is completely worn out by the bad assembly and there are some grooves where it rests - can that pin/dimple be replaced and does it matter that that area has a groove? Otherwise, everything else looks good to me. Maybe I should take it to Jerry and see if he can fix? Or can you tell by the pics if it can be fixed or not?

Note how busted this roller bearing assembly is after removing the crankshaft cover.

The bearing assembly between #1 and #2 pistons is completely busted. I am worried about some pitting where that assembly is attached -- assuming I can buy new parts for what is shown here.

This is a shot of my biggest concern. The silver dimple is worn down and there are grooves from the damaged part.

 

[Nordin]

Re: Force 120 with low compression seeking advice

You need this pin/dimple , it keep the bearingcage in place and prevent the hole cage to spin. In your case the cage has started to spin heated up the plastic and then it start to swell.
Clean the surface with fine sandpaper, also check the surface of the crank. If it is dimpled you have to use fine sandpaper to it.
The surface is importent, it has to be smooth. If not you will have noise from it AND the bearing will be distroied.

To replace the pin/dimple might be hard to do. I have never done it so I have no experience. The pin is pressed in and I think it is hardened.
Maybe jerryjerry, Frank A or someone else here on the forum have experiens from it.

 

[jerryjerry05]

Re: Force 120 with low compression seeking advice

The pin is pressed in.
Probably gonna be a bugger to remove.
But it can be done.Torch/maybe a drill press???
F85909-1 BEARING LOCATING PIN Under 2$
The crank??? It should be taken to a machine shop and see if they can clean it up without removing too much metal.
It might clean up with some very fine grit paper.200g
If you can knock down the high spots you might be able to reuse it??
Pretty sure they don't make bearings oversized.

I can't help with the fix other than post once in a while,going back to work.
There's a good machine shop that I use in Ft.Pierce.
You told me once where you live?is it anywhere near there?

 

[jdamron]

Re: Force 120 with low compression seeking advice

Thanks Jerry for the advice. So I went ahead and ordered just the bearing locating pin. I know I will need other parts but I figured I would first make sure a machine shop can replace the pin before I order the other parts. I live in Winter Garden, which is west of Orlando so Ft Pierce is a pretty good trip. I used a machine shop in Orlando a few years ago to do a valve job for my GrandAm and they did a good job so I might just stop by there once I get the pin and see if they can do it. Thanks.

Also one other quick question - are they any special tools or procedures involved for removing and replacing the "ring snap" that holds the "BEARING ASSEMBLY-CENTER MAIN" together? I was thinking of removing the other two that are still working to inspect those bearings and compare the surface of the crankshaft behind those to the damaged one. And I was worried about overstretching the good ring snaps.

 

[jdamron]

Re: Force 120 with low compression seeking advice

Okay, I know it has been forever since I did my last post on this thread, but I was waiting until after the holidays to take the damaged engine parts into a machine shop to have it looked at. So here is the advice I was given - the machine shop I went to said it would be unreliable to try to fix the damaged engine parts (see pictures in previous posts above). Basically, the crankcase itself has pitting from the destroyed bearing cage that cannot be smoothed out because it is hardened steel, and even if they could smooth it out there are not any over-sized crankcase bearings that could be used so it would not have a good fit. And the set pin would be very difficult to replace and the grooves in the block itself are not worth trying to fix.

So, anyway before I consider the whole outboard complete scrap I was searching to see if I could find used crankcase and block that would be compatible with my system. I found on eBay a used block for $125 and a used crank for $125. But they are for a 1994 Force Outboard 120hp. And I am pretty sure my engine is a 1995 Force 120hp. I was wondering if someone could tell me if that would be compatible. I know there is some risk in buying used parts, but I really do not want to purchase them if they would not fit. I would appreciate any opinions on if these parts would fit by system.

94 Mercury Force Outboard 120HP Cylinder Engine Block | eBay

94 Mercury Force Outboard 120HP Crank Shaft | eBay

If I could use the parts above to put everything back together it would be about $300 plus gaskets plus I would probably want a machine shop to do the rings and boring. But I am just not sure these parts would fit, especially how would I know my pistons from my old block would fit this block?

Thanks in advance.

 

[SkiDad]

Re: Force 120 with low compression seeking advice

Okay, I know it has been forever since I did my last post on this thread, but I was waiting until after the holidays to take the damaged engine parts into a machine shop to have it looked at. So here is the advice I was given - the machine shop I went to said it would be unreliable to try to fix the damaged engine parts (see pictures in previous posts above). Basically, the crankcase itself has pitting from the destroyed bearing cage that cannot be smoothed out because it is hardened steel, and even if they could smooth it out there are not any over-sized crankcase bearings that could be used so it would not have a good fit. And the set pin would be very difficult to replace and the grooves in the block itself are not worth trying to fix.

So, anyway before I consider the whole outboard complete scrap I was searching to see if I could find used crankcase and block that would be compatible with my system. I found on eBay a used block for $125 and a used crank for $125. But they are for a 1994 Force Outboard 120hp. And I am pretty sure my engine is a 1995 Force 120hp. I was wondering if someone could tell me if that would be compatible. I know there is some risk in buying used parts, but I really do not want to purchase them if they would not fit. I would appreciate any opinions on if these parts would fit by system.

94 Mercury Force Outboard 120HP Cylinder Engine Block | eBay

94 Mercury Force Outboard 120HP Crank Shaft | eBay

If I could use the parts above to put everything back together it would be about $300 plus gaskets plus I would probably want a machine shop to do the rings and boring. But I am just not sure these parts would fit, especially how would I know my pistons from my old block would fit this block?

Thanks in advance.

i know the gear case is different between those 2 years but not sure of the block. Might be easier to just pick up another full engine on craigslist. I see them for 500-1000 at times. Or even pick up a Merc 90 or 125 since I think your controls would work with a merc.

 

[pnwboat]

Re: Force 120 with low compression seeking advice

1994 - 1995 there was a change in the pistons. It's hard to say. It looks like the crankshaft will work, however, there is a chance that the pistons will not work. It looks like the 1994 120HP motors used the smaller diameter pistons than the 1995 120HP motors. It's really hard to tell unless you get actual cylinder bore measurements from the two blocks. Or if you're willing to take a chance and possibly have to spend around $300 for all new pistons.

 

[Jiggz]

Re: Force 120 with low compression seeking advice

You might want to consider just getting a used powerhead from a boat yard or ebay and then using this broken one as parts bin. I think this is a lot easier and more cost effective. Or even better, just buy the whole motor which sometimes even comes with a damaged boat and trailer for less than $1K.

 

[jdamron]

Re: Force 120 with low compression seeking advice

Thank you for the replies. Yeah, I would hate to buy those parts and have them not work with the current pistons and everything else that I have. When I zoomed in on the 1994 transfer port covers one of them looks a little different from mine as well. I was thinking it might have just been a change in the fuel pump design. But if the pistons are different size that would be bad. From what I can tell all the other parts I have are in good condition, but I may be better off just getting a whole new used engine as suggested. I think I will just look around some more and see what else I can find. Thank you.

 

[Frank Acampora]

Re: Force 120 with low compression seeking advice

You also have the Mercury lower unit. If the 94 crankshaft was used with a Force lower unit, the crankshaft will have different splines and will not work. Ask before buying.

 

[jerryjerry05]

Re: Force 120 with low compression seeking advice

Probably not gonna work.
Mercury did a few changes.
Keep looking on E-bay and Craigslist.

 

[sjbs]

Re: Force 120 with low compression seeking advice

If you have a 95 block I think the 94 block on Ebay would work.The pistons,rods and crank changed in 96.Call the seller and see if he can give you some numbers off the block and see if he will send you some pictures of the block at the rod journals.Ask him about the splines on the bottom of the crank. Steve.

 

[Frank Acampora]

Re: Force 120 with low compression seeking advice

You can make your life easier: Chrysler and Force measured their bore in decimals. That is the bore was either 3.3125 or 3.375. Now, if you don't have a caliper, that would equal 3 5/16 and 3 3/8. SO: You can measure the bore yourself.

Now, I think--and take this for what it is worth-- I think Force 120 blocks were ALL 3 3/8 bore. The 125 was always 3 5/16 bore.

When Mercury changed the engines in mid 90s, they did not change the block. The crankshaft was given larger diameter crankpins and longer connecting rods. Pistons were changed with a larger wrist pin set higher in the piston body to accommodate the longer rods. HOWEVER: older style pistons and crankshaft assemblies will still fit in the same block.

THUS, if your crankshaft is still usable it will work in any block that has the same bore as your block. Simply measuring the bore will tell you what you need.

If your crankshaft is NOT useable, then you MUST buy a crankshaft splined for the Mercury driveshaft.

NOW: As far as repairing your existing block---These blocks were pinned together before interior finish machining was done. The front and rear halves are a matched pair and can not be swapped. HOWEVER, they can be milled about .010 and the bearing saddles re- line bored with the two block halves bolted together to clean them up. BUT, now you are getting to the point cost wise where it is not economical and your machine shop may not have the equipment to line bore the bearing seats with the two block halves bolted together.

See my private message to you.