Gale,
It is claimed that overuse will eat seals and gaskets by folks that have learned the hard way in auto forums.
That's why I don't want a double bowl carb with it in there over winter even at the prescribed dose.
There may be no harm in it, but I'm old and have learned my share the hard way too.
Very interesting info.
This summer we picked up a 2000-2002 Polaris 325 Magnum ATV. It had one dirty fuel tank so we put in 8 oz of Seafoam and about 3 gallons of Shell V-Power 93 octane on the way home with it.
Over the summer we replaced rubber fuel and oil cooler lines and new valve adjusting port covers and some other wear items. We got it to running again but needed to readjust the carb but when we got around to it the rubber tip on the float shut off needle had failed and it filled the cylinder and crankcase with gas that was treated with Sea Foam so we rebuilt the carb. The carb bowl over flow stem was stopped up but it was cleared during the carb rebuild.
When I was warming it up to set the carb it was running with good power at the higher RPM then it just lost power and died.
The compression tested out at about 35 PSI or 1/3 of min it should have had. When connected to the air compressor it will air up to about 25 PSI max and air is coming out of the breather tube and dip stick hole when the plug is removed. Both valves are closed with no air flow noise coming out the intake or exhaust.
I have never seen a motor that would start and run with power go to low compression in 10 minute time. Unless they broke I know the rings did not wear that much in a few minutes. A leaking head gasket crossed my mind. It was never ran with gas in the crankcase and we brought up the oil pressure several times with the spark plug out to insure new motor oil had pumped everywhere before starting it.
Over the summer we did circulate Marvel Mystery Oil (MMO) through the crank case with the plug out using the starter just for the heck of it to remove carbon build up that may be in the engine. After falling flat on my back 15 Sep it was not able to do much myself.
Friday it is to be 60F (open garage) so we may pull the cylinder head to check the head gasket. We have already pulled the top cover to look at the cam shaft and automatic compression release but both were fine and the cam lobes are still at factor new specs.
I was planning to look at the rod bearing but it is a leaking head gasket I may skip that on this ATV but go ahead and replace the rings since we are only a few bolts away from getting to them when we check the head gasket. We have the bore cam so we can look down the timing chain hole and see if we can see if the head gasket is leaking at that point for the heck of it.
Late summer we picked up a 2002 twin ATV as a project with a known engine knock due to the guy blowing an oil cooler hose going down the road and pumping out the oil. I am using the ATV's to teach engine rebuilding to the kids so it it more a learning project than a riding project.
We do want them both running well by spring. The non running ATV may or may not have crankshaft damage. We are hoping new set of rod inserts will fix the knock and we can do it without splitting the crankcase.
I can see between Seafoam, MMO soaks all summer then a gallon of gas flowing to the crank case after filling the cylinder it may have cut out carbon sealing the head gasket. On top of that after we drained the oil (only pure motor oil came out of the plug at first) because gas came running out when we went to check the oil it was hydro locked and the starter could not turn it over but the straight gas would have put a lot of pressure on the head gasket when it tried to turn the engine leading it to fail after 10 minutes.
On Ebay I did see a cylinder (jug) for sale and showed a build up of carbon from the cylinder to the timing chain space. A head gasket leak at that point would pressurize the crankcase because the head gasket would still be sealing the timing chain passage to the outside world.
After talking about all of this I am looking forward to getting the top end torn down. We have purchased from different sources off Ebay a complete top end of high quality (in spec) because we review what we are going to do before we open the engines. I have a new top end gasket set and a new set of rings so it is the head gasket leaking we have the parts to fix it on hand. If the cylinder or piston has failed we will got back with the tight used ones.
Thanks for your comments about Fuel Treatment and Seafoam over dosage concerns.
After posting I realized how long it was. I had written it in two or three stages over the last hour between other things. If the blown ATV engine is due to overuse of (fuel stabilizer) Seafoam/MMO/gasoline soaking of head gasket under pressure I may come back and move this into an engine rebuild tread.
