coolant leak cause engine to rev? - Snowmobile Forum: Your #1 Snowmobile Forum

wheelseml · 11-04-2012, 07:02 PM

Hi guys I'm new to snowmobile forum and I'll fill you in on my situation. I bought a 1997 Mach1 700 tripple last spring as a project and am trying to fix it up. I'm not a mechanic as such but I'd like to be. I know I picked a hard sled to learn on but its what I got. Anyway, the head was leaking coolant so I took it apart and put all new gaskets and o rings on it and torqued it back on. when I started it, it revved like it was sucking air. I opened her up again and found that when I put the head on one of the ring gaskets separating the cylinder from the "water jacket?" must have slipped out of place an got pinched. coolant in the cylinder. My question is would this cause the engine to rev like hell? I also had the carbs off to clean them but im fairly certain the boots are leak free. let me know what you think?

JheLrey · 11-04-2012, 07:35 PM

An air leak will cause an engine to rev, not coolant. Put it all back together and spray carb cleaner around the motor as it is idling. If it revs up when you spray in a certain spot, you have an air leak which means new gaskets.

wheelseml · 11-04-2012, 08:09 PM

So your saying that there is another leak besides the one letting coolant in. Or could it be the same one? I don't understand how air could get in the cylinder without passin through the coolant chamber. machine won`t idle to check for leaks it just revs like crazy. Im going to seal it up with loctite 518 when I put the head back but Im scared that Im missing something. Wanted to check with someone who knows before I sealed it up again. Any knowledge or tips you might have would be greatly appreciated. thanks

**RJ Gleason** · 11-05-2012, 05:21 AM

NO!
When you put the O-rings in place, use a light coating of grease to hold them in the grooves.
Then make sure that the carb slides are not hanging up before starting.
If the carbs are right, then test for air leaks around the carb flanges and cylinder bases and crank seals by spraying starting fluid at them.

**kccats** · 11-05-2012, 05:28 AM

There is a great carb cleanning section in th How too section!
Your about a bit late, but you might want to pull the motor down and start fresh with all new gaskets and seals?

wheelseml · 11-05-2012, 10:13 AM

Thanks for the help guys I'll let you know what happens. I'm sure I'll be asking more questions before I'm done.

wheelseml · 11-14-2012, 08:10 PM

Hi guys. Well I sealed the head back up again. Set the carbs, (right, this time) and started it up. Seemed to be doing all right this time for a second and then started reving again. Gotta be a leak but I cant really work on it till the weekend for fear of waking the kids. The thing that puzzles me is that the machine was running pretty good before I started frigging with it so that makes me think its something I did. I never touched the the bottom end of the engine. still the original gasket under the cylinders so it makes me think the leak is carb boots but there is no cracks as far as I can tell. A few questions I would like to have answers to.
What does it mean when foam comes out of the exhaust? Coolant?
Is it possible that I disturbed the crankcase Gasket when I torqued the head down?
And would the exhast power valves in any way cause the engine to rev?
Any replies would be appreciated.

Renagade · 11-14-2012, 08:26 PM

the exhaust valves will cause poor performance
at low end if sticking open.
foam from exhaust is from condensation
and oil in pipe and will go away when sled
reaches operating temp.
welcome to the world of triples,
smooth and fast!!!

i love em!!!!!

wheelseml · 11-14-2012, 09:21 PM

One more question. I cleaned the outside of the engine with degreaser and some carb cleaner. No chance they would effect the lower gasket?

Renagade · 11-14-2012, 10:00 PM

nope. if you torqued down jugs or
didnt remove them your good.
i use simple green all over my
sleds to wash them after the
season is over. works great!!!

**kccats** · 11-15-2012, 02:57 AM

Try spraying starting fluid around the carb boots and shaft seal! Go back threw the carbs and syc them too!

wheelseml · 12-03-2012, 09:24 PM

Whats causing one cylinder to fill with gas. sparks good. I mean the gas is just spraying out the exhaust. Took the slide out and noticed that gas was just sitting in the chamber and boot. Took the carb off and drained it and blew into the gas line nipple while turning carb upside down and the floats stopped the air flow so I think thats working.
Educate me please.

**kccats** · 12-04-2012, 06:25 AM

When you have the carb upside down WHERE did it shut off? It needs to be at 'Level' with the carb flange!

wheelseml · 12-04-2012, 07:47 AM

The carb was in my hands when it was upside down. Blowing in the gas entry and flipping the carb was a test to see if the floats were working to stop gas flow. They are. What would be the most common reason for a ridiculous amount of gas flowing threw the carb.

wheelseml · 12-04-2012, 03:16 PM

Hey kccats. Missunderstood what you said what did you mean?

**RJ Gleason** · 12-05-2012, 01:59 AM

The float arm should be parallel to the bowl flange when you hold the carb upside down.
If it is going past parallel then it will allow the bowl to over fill.

wheelseml · 12-05-2012, 05:42 AM

Thanks I didn't know that. I'll check it out.