Force 125 (1987) Cylinder Help

[grininmonkey]

Re: Force 125 (1987) Cylinder Help

I just took of the lower manafold/reed and before I did, I observed a lot of fuel/oily build up on the bottom and it seems to have been dripping off on the support plate area for some time. The image doesn't show it well, sorry I tried a few times with my phone but it's the best picture I could get showing where I have a lot (and I mean a lot) of fuel collected inside and where it was collected on the manafold.

Would this be normal being the bottom of the crankcase and all?

By the way, the reeds look perfect and all blades are resting closed, in fact, I would gander that they are not original.

 

[Jiggz]

Re: Force 125 (1987) Cylinder Help

Puddling of fuel is more likely caused by a bad fuel recirc system but most likely from prolong idling. These 2 cycle motors fuel recovery system can only work when running at high RPM and never on idle. From this pic you can start removing the main bearing caps and pull out that piston and conduct a check on the cylinder. If the cylinder is good, you can go on with measuring the bore to make sure you order the right size piston and rings. I highly recommend using Wiseco kits which comes with rings installed already but requires a different wrist bearings which you can also buy as a kit. You will reuse the rod and caps and also the roller bearings so make sure you account them all.

 

[grininmonkey]

Re: Force 125 (1987) Cylinder Help

I spent the afternoon trying to find a 12-pt 1/4" socket at some local parts stores etc... nobody had one. So I'll likely have to use Amazon or something.... sucks!

 

[pnwboat]

Re: Force 125 (1987) Cylinder Help

I found a 12 point 1/4" socket at my local Sears store.

 

[Jiggz]

Re: Force 125 (1987) Cylinder Help

Sears or ACE Hardware is probably the only local store who sells them individually. Or as you mentioned online also.

 

[jerryjerry05]

Re: Force 125 (1987) Cylinder Help

Any Snap on or Mac truck will have it. Like pnw says Sears. It comes stock in most of their little socket sets.
I have 2, 1 in 1/4" drive and 1 in 3/8drive.The 3/8 fits my tourqe wrench. Both from different Sears kits.

 

[grininmonkey]

Re: Force 125 (1987) Cylinder Help

So I ordered a socket and got the piston off, and when I pulled it out, both roller cages dropped in pieces with the rollers. I assume the roller cage is not suppose to do that, correct?

Looking online at boats (dot) net, that simple roller cage is more than the replacement piston itself, must be a mistake?

Anyone have an a roller cage set they would sell?

 

[grininmonkey]

Re: Force 125 (1987) Cylinder Help

Crap, I may be totally screwed. The inner diameter (cylinder bore) measures 3.405 and the piston itself measures 3.395 which is way out of spec. Another thing is the piston I pulled out has Vertex 1311 written on it, which results in a brand of pistons for ATVs. Somebody might have bored it out and monkeyed with it.

CRAP!!!!

 

[grininmonkey]

Re: Force 125 (1987) Cylinder Help

Humm... I noticed in the diagrams in the manual I have, that my cylinder head plate does not match the year the motor plate says. The trim plate says 1251x87B but the motor support plate with the serial says 1254X88C. According to the diagrams and the shop manual, all the cylinder heads before 1991 where flat, and mine is narrow with reeds ( I think you call it that ) and when I look up the piston/bore specs for 1991 120HP, the dimensions I am measuring are in spec. So I wonder I someone swapped a newer 120HP power head. Is there any other accurate form of identification of the power head?

My cowl has the 125 stickers, but the cylinder head shape and the piston/bore size say something else?

 

[Frank Acampora]

Re: Force 125 (1987) Cylinder Help

125 was always a 3.3125 bore. Your engine has exactly a .030 overbore from 3.375 to 3.405. A 125 can NOT be bored out to 3.405. THUS: You actually have a 120 block.

One thing you should do is to check the crankpin throw. The 120 was 2.80 and the 125 was 2.875. Putting a 125 crank into a 120 block will actually reduce power delivered because you are effectively changing port timing.

 

[grininmonkey]

Re: Force 125 (1987) Cylinder Help

I am pretty sure I have an 1254X88C 125HP like the plate says. Several parts which have part #s stamped match up to an 1988 125. The crankpin throw is 2.87", the connecting rod even has 88 after the part number stamped on it which belongs to the 1988 50,125 and 150 blocks. I just measured the other cylinders (bore) and the other three are 3.36" which is around the max .040 oversize on a 125 block.

Someone must have bored out the #4 to 3.405 and used a 120 piston because it was already maxed out as the other 3 are. I already found and ordered a new piston off ebay I found for 70 bucks, and since it was running fine (with the exception of cutting off in idle after a few minutes) I'm going to go ahead and get it back together like is. I have already spent to much this year to cut a loss and get another powerhead. I wish I could just replace the cylinder but I seem to only be able to find pulled (complete) powerheads for sale.

Perhaps it will be fine/functional for the rest of this year?

 

[grininmonkey]

Re: Force 125 (1987) Cylinder Help

I spent 3 hours today in the hot sun trying to get the roller cage & rollers to stay in place in order to put the rod clamp on thru the manifold opening... this is proving to be very difficult, not sure I can do it, I was very close once but no joy. :-(

 

[Jiggz]

Re: Force 125 (1987) Cylinder Help

I used two tricks to accomplish this. One you need a long (18~24 inches) 1/4 wire rod (I got one from those mail box round reflectors from Ace Hardware) and second you will need triple guard grease. This grease is so thick it is almost like dry molasses and really sticky. Use the grease to hold the rollers and roller cage in the caps. Use the wire rod to guide the cap doing the following. Insert the wire rod from the intake side passing thru the cylinder and into one of the holes of the upper cap (part of the piston rod). Push in the piston while guiding the rod cap (with the wire rod) in place to align with the crankshaft journal. Next from the other end of the wire rod (from the intake side) insert the bottom cap (with rollers and cage installed) through the wire rod and slowly guide it to the crankshaft journal using either a long needle nose or another wire rod. When the bottom bearing cap matches the crankshaft journal, start one of the cap screws just enough to hold the two caps together (assuming you used a needle nose pliers but if you used a second wire rod, you just have to remove the 2nd one). Remove the wire rod (or remaining wire rod) and install remaining screw. Torque and you are done with the cap bearing installation. Sometimes you might have to move the crankshaft to align the piston rod caps to the bearing journal or just for easy access.

 

[grininmonkey]

Re: Force 125 (1987) Cylinder Help

I'll be doing an attempt later this evening, doing what you said, except I'm going to use frozen vaseline. I'm worried triple guard would gunk up? The vaseline should dissolve and work it's way out... I'm thinking anyway. Cross my fingers I can get this darn thing together!

 

[grininmonkey]

Re: Force 125 (1987) Cylinder Help

A couple of days of rain delayed my activities... but today, frozen vaseline worked like a charm, I had the piston in and clamped in one try. Because I can't see in there well I'm hoping all rollers are in there. I ran the piston back and forth many times to make sure nothing was blocking (dropped roller). I hope to put everything back together of the next couple of days and see how it runs.

 

[Jiggz]

Re: Force 125 (1987) Cylinder Help

I guess frozen vaseline works also but as I said, the triple guard grease worked well for me. Anyways, congrats and hope she will be running soon.

 

[grininmonkey]

Re: Force 125 (1987) Cylinder Help

Update***

I ran the boat in the lake doing break-in runs for 2 hours this past weekend. Motor seems to be running really good with the exception of a lot of extra smoke which I hope is just from the fact I have double the oil mixed for the break-in. I hope the fact that #4 cylinder is over-oversized will not cause problems for a season or two. Compression is 145,145,150,151 and she cranks on one full turn of the flywheel. The motor is also a lot more quite than it was originally, and WOT has no flutter and vibration, just purrs away.

Keeping my fingers crossed that it stays this way so I can have some late season fun ;-)