Logo
FULL SITE MENU

95 force 90hp rebuild

N

nickhaulotte

Regular Contributor
Hi all, I am in the process of rebuilding my force motor. I have read forums on how to get the motor out and have been succesful. I do have repair manual as referance also.This will be my first overhaul. I now have the motor broke down( pistons and crankshaft pulled). The source of my whole problem is a ring broke on piston 2 and got caught on the exaust and bent the edge of the piston.I dont see or feel a grove in the block however will take to a machine shop to see. Also want them to check "out of round". Allthough, as i pulled the other pistons out i noticed # 1 also has a broken ring. My question is: Is this common and what would cause this to happen? I dont want to repair and have the situation arrise agian. Also, will keep everyone posted on my progress these forums are helpfull. thanks all, nick
 
Broken rings are NOT common.Not enough oil in the gas or water in the fuel.Timing off, over heating.Could cause these things.Profile??J
 
Thanks jerry, The fuel and oil mix running at high rpm is the only thing i could come up with also. I started using a walmart brand of oils late last season and noticed the performance of the engine was declining and smoking more. I will remember not to use this oil agian, i was trying to save a couple bucks. but i could have done my math a little wrong while filling up also. I will be finishing up the stripping of the block and hopefully get it into the machine shop tomorrow. Thanks, Nick
 
also is there any better way of marking timing other than tdc? May be a little late for me now if there is but at least i will know in the future. Thanks
 
Thanks jerry, I dropped block off to get honed ( I think) today. If roundness is ok then that will all that will be needed. I am getting excited to get back into this project so hopefully it wont take them too long but can wait for a good job. I was also wanting your opinion on if i should rebuild the carbs. I think i should beings i am this far into the project. What do you think? It will give me something to passify my time on waiting for the block..... Nick
 
Not so much rebuild as most just need a cleaning.
Take them apart and see how much garbage and gunk is built up.
There is a reason the rings went bad and maybe the carbs were the problem.
Take a few pics of the inside and post them.
Most rebuild kits don't work .You usually end up re-using the old needle anyway.J
 
Thanks jerry, I cleaned my carbs on my bike last year and couldnt believe the differance it made in performance. Also, I talked with my cousin tonight ( He went to mmi in pheniox) and he said the same thing you just did. Granted he is not a marine mechanic, but took a few classes on them. He is more specilized in dirt bikes. He was asking if they were vacume carbs or float. I could not give him a answer, to me they look like float carbs but he may have been trying to ask me something I wasn't understanding. But thanks agian for the info, i will get the carbs opened up in the next couple days and see and post some pic. I am a little leary since i dont have my manual on hand. Also, does the Clymer version have the static timing in it and is this manual a good one to use. I have used one on my bike when i was rebuilding it and it worked great. I ordered one for this motor also. Thanks again, Nick
 
Get factory if possible.Way better than Clymer.Don't know if Clymer has the static timing,never use it.J
They are floats.
 
Jerry, I got the block back from my machine shop. They just power honed the walls, And did a wonderful job on it. Now my problem is should i work just the one piston that got a little ding in it or buy new ones. The parts for this block is very limited ( as my pockets) I have filled the top of piston to smooth so it will mate to the head without wear but there is a grove cut accross the top ring area about 3/16 of a inch wide. I think the ring should span over this with no problem. Thanks nick
 
Hi all, I have some questions concerning piston specs for this motor. I cant determine if the sizing is too far out of specs. my plan is to just put new rings on and go but...??? Here is the sizing (od)
piston measurment pulled parrellel with conn. rod bore
top bottom
#1 3.361 3.371
#2 3.371 3.372
#3 3.359 3.369

specs are as follows for above
3.367-3.368

Measurements pulled 90 degrees from conn. rod bore
top bottom
#1 3.360 3.364
#2 3.359 3.364
#3 3.360 3.362


cylinder wall (id)
#1 3.376
#2 3.376
#3 3.377

Spec is 3.3750-3.3762
 
These are the before and after photos of the piston that got dinged due to broken ring. the grey area in first photo is where i repaired
 

Attachments

  • nick 339.jpg
    nick 339.jpg
    31.7 KB · Views: 160
  • nick 251.jpg
    nick 251.jpg
    30.2 KB · Views: 145
This is one of the other pistons (#3) it has some scoring is what I am calling it. basically, the horisontal lines in pistion skirt are not longer there now there is vertical lines in skirting. I have no idea what caused this but i have filed down all the rough edges and measurements are listed above. Do you think this piston will be ok? I think it would be ok since nothing will be draging. I would like to know what could have caused this though. Was this one piston pinging maybe? i would think all would show signs if this was happening. It has me a little confused since the rings on this piston were not broken. Maybe just wear and minor "shavings" from the rings caused this? Since this was the worst scratched cylinder sleave. Thanks a bunch jerry. If you ever have any questions to do with your home feel free to ask me since that is my profession.
 

Attachments

  • nick 340.jpg
    nick 340.jpg
    29.7 KB · Views: 97
The scoring is not a good thing.Replace that piston too.It will just cause more damage.It should be smooth.Possibly got hot and started melting,carbon build up??
I'd replace it.
The 1st piston? The #s on the top?? Does that say 10?? If so that piston is already .010 thou over.
Used parts that aren't perfect will cause premature failure.J
 
Thanks again jerry. I am having trouble finding pistons now. New ones that I have found are 3.375 in diameter. My cylinder walls are 3.376. That seems like to tight of fit beings specs for pistons are 3.370
 
So I ordered the parts today. Three new pistons and rings ( included was wristpins and retainers) New impellar and t stat. And gaskets. I will size the pistons when they get here and determine if i need to take the block back to a machine shop to get bored 3 tho or so. Does anyone know the recomended clearence between piston and bore?
 
Hi all once agian. Last night I opened one carb up to clean and noticed that there was no varnishing in any jets,or in the bowl. I am thinking that this is because mixed fuel being used. I think the oil in the gas is preventing this from happening. I still plan on using chem dip on the parts that will accept them. But am getting new gaskets to put on. My new parts should be in friday so I will be building a engine this weekend!!!! Hopefully, I can get back to fishing when the weather breaks here since we have had record highs (107 f) for the last month, And a record drought ( think we are going on day 45 maybe).
 
Just be real carefull when reinstalling the crank and the crank seals.The crank should be able to turn buy hand.
Make sure the spaghetti seal(if you have it) is seald at the ends and use a good silicone.I use Permatex Black.
I sent you a pm.J
 
so Far progress is moving right along. I have installed the new conn rods to piston and hopefully by the end of today will have a short block agian. Hope by next weekend I will be fishing again.
 
It has been a slow and painfull process but I have the pistons in the bore and have the connecting rods bolted to the crank. Getting closer!!!
 
Well, got the motor put back together. New pistons, rings, wristpins and retainers, new crank seals, block honed, rebuilt carbs,new plugs, fluid, Timed and tuned carbs and been out on the water. I am using a 25-1 fuel ratio with 91 octance and quicksilver lubricants. I have noticed a have a noise coming from the powerhead wile running 3000 rpms and higher. The sound is like a racheting sound, does not sound like "pinging". I have a fealing this is a bearing (lower main) since that is where the sound appears to be coming from. But I would like some input on what other people may think. Thanks all
 
Back
Top