96 formula III 600 engine failure - Snowmobile Forum: Your #1 Snowmobile Forum

jnugent4 · 02-06-2008, 01:35 PM

Any idea of the problem. It appears that cylinder ran out of oil.
Started engine let it idle in driveway for 20 min. Rode it for twenty minutes less than 30 mph. When we got to a small lake it shut off. Tried to pull it with cord but was hard to pull. Tried again it loosened up and started then ran for ten seconds and the picture is the result. Mechanic says it looks like oil problem on that cylinder. I understand that a leaky crankshaft bearing seal could lean out engine and cause same problem. is there any way to check for a leaky crankshaft seal. No problem idling before the engine seized. The mechanic is disconnectine the oil pump and is suggesting to premix the gas 40 to 1 . Any comments

**smallengineguy** · 02-06-2008, 05:22 PM

The picture isn't the best, but it indeed looks like a lack of oil seized it. If the piston wrist pin is bluish colored, that's a sign of oil starvation also.

upersleder · 02-06-2008, 10:44 PM

you have one oil pump, three lines out, if it was lack of oil from the pump you would have damage on the other two cylinders, i would check the line and be sure it is ok and not plugged, but i think you may have had another issue such as the pto seal. while its apart, drill the hole for the PTO bearing and make sure the crank and big end of the rod bearing is good.

yama_rocket05 · 02-17-2008, 07:28 PM

did you blow a belt recently. Those machines were notorious for blowing the belt and taking out the crank seal on the pto cyl. I had the same issue on a 97 f3 I had.

jnugent4 · 03-13-2008, 09:49 AM

thanks guys for replying. I was wondering if anyone had pictures of the land you have to drill out to fix the PTO bearing failure problem

jnugent4 · 03-23-2008, 05:23 PM

I have a 96 formula III LT with PTO piston failure I am posting some pics for comments. does this look like oil failure on the pto side or a bad crank seal
Note picture with piece out of the piston . Is there any way to see if crank seal problem by pressurizing the engine to 5 psi and it should hold for 3 minutes according to shop manual. I want to disconnect the oil pump and mix the gas to be sure. i assume that 40 to 1 is a good mix. What is the best way to remove the oil injection.

PoisonJello · 03-23-2008, 06:24 PM

you say it seized the one piston, lack of oil but did you check the other piston to see what they look like?

yama_rocket05 · 03-23-2008, 06:35 PM

When you have a no oil problem usually the crank goes. My 97 f 3 did the same and it was because I blew a belt and some got wrapped around the crank and took out the seal. If you can take off the clutch and check the seal. Also pull off the oil pump and spin it with a drill while holdin the pump arm wide open and see if it is pumpin. It looks like zshe leaned out by the pic you sent.

**smallengineguy** · 03-23-2008, 07:06 PM

[quote=yama_rocket05]When you have a no oil problem usually the crank goes.[quote]

USUALLY when your oiler goes, it'll seize the top end first, due to the lack of oil mixed with the heat of the hot cylinders/pistons burning the rest of the oil off. Looks like that's what yours did. Premix the fuel 50:1, and remove the hoses from the injectors to the carbs and block the fittings.

jnugent4 · 03-24-2008, 05:14 PM

Thanks guys

Im new at small engines this is my first tear down and rebuild. I gave up on the mechanic and decided to do it myself. I had the machine in to him since Jan. I was working on it again today and the oil pump is sticky and doesnt return to idle position reliably. I also forgot to mention that the thermostat goose neck was leaking and I see what I assume is antifreeze (green color) in the seized PTO cylinder. Would antifreeze cause the piston damage and how do I make sure that its all gone from the crankcase and crank bearings. I bought a new cylinder and piston but want to make sure I get the root cause otherwise it will seize again. I didnt take off the other two cylinders yet. It appears that the three injector hoses leave the pump and are attached to the engine just below the carbs. I thought they would go to the carbs themselves. How do you verify the PTO crank seal other than inspection. I would assume that you pressurize the cylinder when BDC ie exhaust and transfer ports covered and 5 psi into carb ports to see it is leaking

Thanks to everyone for helping a newby out.

**RJ Gleason** · 03-25-2008, 04:03 AM

Coolant can and will cause a piston failure due to making the cyl run lean.
To get the coolant out of the base, take some paper towels and twist them up tight and stick it into the base, it will wick up the moisture, repeat as necessary. You can also use a shop vac to get larger amount out, spray the inside with WD-40 and then put some regular 20wt in there and work it into the bearings.

**smallengineguy** · 03-25-2008, 06:11 AM

That coolant is probably what caused your problems to begin with. If the other 2 cylinders are good, I'd leave the oil injection right where it is.

jnugent4 · 03-25-2008, 08:57 AM

thanks guys I am going to take off the oil pump and spin it with a drill to see if there is any oil entering the cylinder. I need to take out the reed first so hopefully I can see the oil. I cant seem to get the oil line off the port where it goes into the engine cylinder there are some crimp on hose tighteners there. How do you get these things off. I aslo wanted to check the crank seal how do you get the clutch and flywheel off the crank. Is a puller required in order to inspect the seal. Lastly do you need to split the block in order to replace the crank seal if not then I will change it anyway

**RJ Gleason** · 03-25-2008, 03:02 PM

You do need the proper tool for removing the clutch, but you can change the seal without splitting the case.

jnugent4 · 04-23-2008, 04:53 AM

just an update guys. I removed the oil pump and spinned it with drill and it looks like oil was dropping one drop every couple of seconds out of the oil line for the bad cylinder. I removed the drive gear and soldered up injectors. I removed the magneto and clutch with proper tool and I am trying to pressurize crank but PTO seal doesnt appear to leak no bubbbles. The cylinder puimps up to 10 pSI but doesnt hold pressure. I put new piston and new cylinder on but didnt check the ring gap how critical is this. I didnt check the piston to cylinder clearance as well . The tops of the other two pistons are completely covered in black carbon no piston wash so is it possible that I have a fuel pump problem with all cylinders running lean.

Im going to post some pictures soon.

jnugent4 · 05-01-2008, 06:14 AM

anyone have a picture of the PTO bearing on a 96 Formula III . I removed the seal yesterday to add some Isoflex grease and noticed that the plastic bearing cage the part tht holds the bearings in place has a cut in it. It appears to rotate fine but I am wondering whether I put a cut in it when i removed seal with screwdriver. The magneto one appears to be a different bearing type. the one on the front is a SKF 6208-TN9 40 mm type.

please help i dont want to split case to remove this bearing if i dont have to

jnugent4 · 05-01-2008, 04:03 PM

anybody have any ideas

**RJ Gleason** · 05-02-2008, 09:10 AM

If it's not cut clear through, just leave it.

**smallengineguy** · 05-03-2008, 05:50 AM

I'd leave it.

jnugent4 · 05-04-2008, 05:08 PM

Thanks guys

I split the case yesterday and today and replaced the bearing. I put three bond 1194 on the cases and retorqued in proper sequence. See picture of homemade press to press new PTO bearing on crank.

Had quite a battle removing the old bearing. Removed cage and put three 1/4 inch threaded rod between bearing races screwed nuts on both ends and used harmonic gear puller to carefully remove old bearing. The special bearing puller I paid twenty dollars for was useless could grip the bearing and I didnt want to pull crank completely out.