trying to open crank case on force 125

[bcsnare]

Hopefully a simple question.

the powerhead has been removed and most every component is off. basically all thats left on is the reed valve housing (between crank and carbs) and the block itself.

Im having trouble opening the case. I am sure that i have taken out every external bolt, the 6 larger size 9/16(i believe) bolts and all of the smaller 3/8 bolts, and the nuts underneath the block.

are there internal bolts im not seeing????

I've havent tried to "Force" it apart, but it seems like more than glue is holding it together and im not trying to break anything

 

[bcsnare]

Re: trying to open crank case on force 125

ok

found the alan key bolts in the reed housing. i have the right size key but cant crack them loose. i tried putting a wrench around the alan key, but the 9/16 wrench that goes around it is short and i dont know how to get more torque on it. any suggestions?

 

[bcsnare]

Re: trying to open crank case on force 125

nevermind...i got them out. jeez...

end result is it ate the wrist pin bearing on the lower cylinder. two got alongside the lowest piston as it came through the fuel port. I think it is borable so now i need to talk to a machine shop. The rod journal looks suprisingly ok, but the piston is trashed. the top of the head has a couple of nicks where the bearing rollers got pounded against it. I didnt get a firm count of the rollers but i've gotten most all of the pieces(i think) out with a magnet. some of them were blown to smithereen. one of the only whole ones was wedged in the slot on the crank side where the piston bolts on.

I had just replaced a head gasket immediately before this happened. the older gasket had the voids between the cylinders for the water jacket, and the metal ring blew out into this area on the cylinder above the one that took a ****. any idea if this could have happend as a result of the water in the cylinder? someone suggested that the water might have prevented the oil gas mix from lubing the bearing causing it to fail. does that sound right??? i really want to address why this happened if there is another possiblity. i know my oil gas mix was right on and i usually always use the quicksilver. im not putting cheap stuff in there for sure...

Thanks to everyone that has been of help to me. this is a wonderful forum and the information i have gotten on here has been a great help to me.
scott

Should i do all four while i am at it? is there any advantage to doing this if the other cylinders and pistons look sweet? should i atleast do a ring job on the other cylinders if I elect to leave them alone???

 

[pnwboat]

Re: trying to open crank case on force 125

Water contamination will eventually cause a bearing failure, however after looking at you scenario, I don't think this is the cause in your case.

The head gasket failure may be the clue in your case. You mentioned in one of your earlier posts that you took one of the spark plugs out and a significant amount of clear water came out. BINGO! If too much water gets into the cylinder, it actually takes up some of the dead space in the cylinder when the piston is trying to compress the air/fuel mixture. Air/fuel mixture is easy to compress. Water does not compress as easily. I suspect that what you have here is known as hydroloc. The piston cannot physically compress the water. Something has to "give". Depending on how much pressure is generated, you can end up with bent connecting rods, blown head gaskets etc. In your case, it probably damaged the wrist pin bearings (as well as the head gasket).

At this point, I wouldn't worry too much about pin-pointing the exact cause, but inspect the remaining engine components very carefully. Look for discoloration on all the bearings and corresponding crankshaft journals. I know it's almost impossible to inspect the wrist pin bearings in other pistons without taking them apart. Since there is no sign of damage to those cylinders, I would assume they're probably OK. I would take a very close look at the rod on the failed cylinder. Inspect the surface of the small end of the rod where the wrist pin bearing ride. Any surface imperfection or pitting is not acceptable and the rod should be replaced. Also make sure it's not bent. I would have a machine shop check it out to be sure.

If the other cylinders are OK, then I wouldn't do anything with them. This is a personal decision based on cost verses results. Piston, ring, and wrist pin are about $80 a set. Rings by themselves are about $25 a set. When it comes to these 2 stoke outboards, the old saying "If it ain't broke, don't fix it" rings true. I've been bitten several times trying to be overly cautious. But then again, that just my experience and by no means applicable in all cases.

 

[bcsnare]

Re: trying to open crank case on force 125

I follow you with the idea of hydroloc. I had assumed that the water got in as a result of the head gasket blowing allowing water from the surrounding jacket to enter. If i read your post correctly, you suggested that the water caused the head gasket and bearing failure instead of vise-versa. Could you clarify what you meant?

I figured an old head gasket blew (it had openeings betweent he cylinders as opposed to solid gasket between cylinders like the new sierra one I purchased), allowed water into the cylinder and crankcase. I fixed the head gasket and did not suspect anything else was wrong...no apparent water in the cylinder, i coul turn the flywheel smoothly, and the piston and everything looked good..., and fired it up the next day. Started up right away and sounded awesome

It ran very nicely in the water for 15 minutes before the click click click stop sieze. I understand the idea of hydroloc but based on the sequence of what happend, how did water get into the cylinder to cause the hydroloc and then blow the head gasket and bearing. I might be confused, i dont know.

Could water have still been in there? but not visible? could that have caused hydroloc? I didnt notice any amount of water when i pulled the crank cover off. No sign of any when i tapped the piston out. The smallest amount of "oil" came out when I pulled the plate off the bottom(4 nuts). it was a very small amount.

I was leaning towards doing only the one. Would you suggest replacing just the rings if nothing else on the other three? they could be 25 years old for all I know and I have it apart... but yes, if it isnt broke dont fix it. whats your take on that?

 

[CharlieB]

Re: trying to open crank case on force 125

You didn't mention the color (blued?) of the rod cap or if the piston skirts appear 'wiped' onto the cyl walls from overheating.

The reason I ask is the older Force ignition boxes sometimes had a failure we call 'cross-firing' or 'double-firing' a cyl. Not noticeable until the rapid power loss and lock up from an overheated cyl.

A double-firing box can be detected with a timing light, that cyl will show the timing mark in two places, or an inductive tach will read twice that of the other cyls.

If this is the case, replace the box BEFORE launching the craft or you WILL be into that motor again, very soon.

 

[bcsnare]

Re: trying to open crank case on force 125

CharlieB as a matter of fact, the bearing connecting the second rod from bottom(bottom one failed) was blueish. I will definitely check that out. the top two bearings were much more polished and "clear". The piston was demolished and the cylinder is scored. At the very least its getting bored out, but most likely its getting a sleeve. the back of the rod (where the 12point bolts are) was cracked length wise and even had a chunk of roller between it. no sign of the race and I extracted several pieces of roller from the fuel intakes and crank case with a magnet. the cylinder above the bottom one looks pretty decent and much like the top two. the rod journal does not seem to have been damaged. its not mirror smooth, but its not pitted or gouged. it kinda looks like the race pulverized leaving this powder coating like dust. Its going into the machine shop tomorrow. I will post some pictures and a follow up... i do have a couple questions though.

3 questions
Could double firing have caused the head gasket to blow originally?

If double firing were the case, would the engine have sounded good by just fixing the head gasket (first thing i did)? That seemed to 'fix" the problem until blam!

Can the double fire issue be an intermittent type thing...such as it happens but not every time or all the time.??

I know i can rebuild it, but like you suggested... I only want to do this once to fix it...lol. I am seriously trying to figure out what the hell caused it. There was a significant amount of water in the cylinder when i initially pulled the plugs which leads me to believe there was a considerable amount getting flushed through the lower half of the crank case.
Thank you for your help!

 

[CharlieB]

Re: trying to open crank case on force 125

Either a double firing ignition OR a dirty/lean carb will cause the cyl and bearing to go lean on fuel AND oil, it can destroy a cyl within minutes. The damage is the same and is difficult to determine the cause.

For these reasons EVERY rebuild, whether only one cyl or all, gets a total carb cleaning on ALL carbs, fuel pump kit, new impeller, and ignition check up on EVERY cyl. The additional expense is cheap compared to a second rebuild because we missed something.