Fuel/Oil ratio on 2010 M8

[Coldfinger]

Have around 500 miles. Riding at 9-11,000 ft. The last three tanks of fuel I monitored oil usage and it seems to be running around 28:1.

Has anyone else calculated what they are running at?

Anyone adjusted the oil pump rod to lean it out a little - if so, how much and what were the before and after ratios?

Thanks.

Jim

 

[Coldfinger]

Does anyone else think their sled uses too much oil?

 

[hatchers]

mine does use too much, going premix when i get the time, screw that silly pump

 

[logchain]

mine runs at about 28:1 also oil, is alot cheaper than a new engin. it seems alot of people think they should be running at 40:1 I wish someone would show me in arcti cat spec. stating 40:1 mix.

 

[Coldfinger]

I agree a little extra oil is good insurance as long as it doesn't negatively affect performance or carbon things up too much.

Here is something to ponder - the oil pump operation is linked to the throttle position. Could it be true that at sea level the fuel/oil mixture would possibly be leaner, like 37:1 or so because more fuel would be used at any given throttle setting?

 

[logchain]

I agree a little extra oil is good insurance as long as it doesn't negatively affect performance or carbon things up too much.

Here is something to ponder - the oil pump operation is linked to the throttle position. Could it be true that at sea level the fuel/oil mixture would possibly be leaner, like 37:1 or so because more fuel would be used at any given throttle setting?

dont know about that. I do know all of the arctic cats I have owend from 1m 900, m7, m1000, to current m8 and sons m7 and m8 all have run about 28:1. ajusted the oil down to 38:1 on the m1000 and seized a piston turend the oil back up to about 32:1 and lost the pto rod bearing 3 rides later. put it back to 28:1 and my other son has rode it this year with no problams. I havent had any problams with performance or carbon at 28:1. late last year I switched from cat oil to amzoil I think its better oil and I can buy it for 15.00 a gallon cheaper. I know alot of people are going to the oil delete and pre mixing. im sure you could get a more consistent fuel oil delivery but it seems they are having alot of crank problams.

 

[backcountryislife]

I run premix & run 32:1, I know a few people that run 28:1, with premix I'd go as lean as 40:1 max, but with the stock oiler you've got too much variable to trust that the mix you think you're getting is consistent through the rpm range.


Btw, since the oiler doens't have a clue where you're riding, I think your theory about the ratio changing from altitude to altitude makes a lot of sense.

 

[skimike]

I checked mine a few days ago for the first time and it was 29:1 so it sounds like we are all within normal range, Im sure they turn it up some to get the engines to live long,and the way I ride Im sure I will get my 2 years warranties worth, I have 1,000 miles now and will prolly ride 4 or 500 more in the next week, we have snow in the forecast for the next 7 days. I ride in California's eastern sierra

 

[Mr. BB]

I'm beginning to wonder if the real culprit or at least just as guilty is the stock fuel map. Seems to be pretty rich in the low range and on up a little which means your getting to much oil right along with the extra fuel. I've got my oil usage right at 40:1, was 36:1 and not going any lower. Plugs are $10, pretty cheap compared to engine repairs. Problem is the stock fuel map could be lean in the upper ranges and then engine is being starved for oil at certain RPM's. Last year I went thru 3 sets of plugs in 700 miles to keep it running good. I turned out the control rod one turn to get 40:1, but plugs are beginning to foul after 400 miles, not good, but better than last year. I suppose a correctly dialed in Power Commander would be the ticket to clean up some of these problems,but.......

 

[logchain]

I'm beginning to wonder if the real culprit or at least just as guilty is the stock fuel map. Seems to be pretty rich in the low range and on up a little which means your getting to much oil right along with the extra fuel. I've got my oil usage right at 40:1, was 36:1 and not going any lower. Plugs are $10, pretty cheap compared to engine repairs. Problem is the stock fuel map could be lean in the upper ranges and then engine is being starved for oil at certain RPM's. Last year I went thru 3 sets of plugs in 700 miles to keep it running good. I turned out the control rod one turn to get 40:1, but plugs are beginning to foul after 400 miles, not good, but better than last year. I suppose a correctly dialed in Power Commander would be the ticket to clean up some of these problems,but.......

I think your taking a chance with your engin at 40:1 using your oil injection I wouldent hold it wide open for very long. why do so many people think 40:1 is were their oil injection shoul be set at. if this was true it would come from the factory set at 40:1 instead at about 28:1. I had to learn the hard way. have never seen any spec. from arctic cat stating 40:1.

 

[Klimbing Kitty]

40:1 is pretty standard if you are running premix. That way you have a constant and you are not depending on a throttle position and an oil pump to put the right amount of oil into the gas. If you are using an oil pump you may want to use a larger amount of oil 28:1 or 32:1 to guarantee a safer engine. With that said the more oil you run the leaner your fuel becomes!! very important to remember

 

[rooster740]

I run premix & run 32:1, I know a few people that run 28:1, with premix I'd go as lean as 40:1 max, but with the stock oiler you've got too much variable to trust that the mix you think you're getting is consistent through the rpm range.


Btw, since the oiler doens't have a clue where you're riding, I think your theory about the ratio changing from altitude to altitude makes a lot of sense.

X2 I also premix at 32:1. I catch hell from the know it all's but I have had no crank issues.

 

[Sergeant HCR]

Are all you guys using Cat's APV oil? doesn't Cat's oil gum up the power valves quickly? On my old 1M, I used synthetic at 60:1 and never had a problem. Granted I am on a totally different machine now.

I am using Cat's oil now as I am still in the warranty period and not taking chances.

 

[Coldfinger]

I've always run Cat APV synthetic but I'll consider other types when my last gallon or two are gone.

Saw another site where someone said there are quite a few engine builders that say Ski-doo brand oil is one of the best from the evidence they've seen while tearing down and rebuilding engines.

Suppliers may play a part too. If the doo oil is the same as they run in their watercraft I can run down to the local cycle shop and buy some, otherwise I have to pick up the APV oil on the road.

 

[Sunridge Sledhead]

Glad to see this thread. I'm mainly riding a 2010 M8. I was just getting ready to ride yesterday and thought, "Man this thing seems to be drinking a lot of oil and running rich!" My doughnut keeps twisting a little off the indented stay and spurting oil around under the hood too. I had the pipe off to take the heat shield and fiberglass dampener off and decided to check my plugs. They were very wet and gummed up, but it was still running well. The sled seems to clean up in mid and upper ranges, but very rich on the bottom, especially if a little cold. I've put thousands of miles on multiple sleds eliminating the oil injector and premixing at 40:1, but no scientific reason for doing so, just what I was told. I've lost one crank and a few top ends. But, I think the issues had more to do with big bores and turbos. This sled is stock with a can, and I love it!!! Good info....thanks everyone!