B&S Kool Bore Snow Engine consumes oil

[boraticus]

I've been using a B&S 305cc Kool Bore snow engine on my Simplicity snow thrower now for three seasons. Before each use I check the oil. I run Mobile 1 5W30 synthetic in it. I've noticed that if I use the machine for an hour or two of average work, the next day when I check the oil, it's down on the dipstick by about 1/8". Every time. I initially thought it was break-in oil consumption but now the engine has 35+ hours on it. So, that's not an excuse.

Over the years, I've operated two ten h.p. Tecumseh L head engines on Craftsman snow throwers. The oil level never varied from day to day use. I used conventional 10W30 in those machines.

Is it just the nature of the aluminum bore engine to consume more oil or could it possibly be the synthetic oil itself?

 

[Steve S]

you said ...I've been using a B&S 305cc Kool Bore snow engine on my Simplicity snow thrower now for three seasons. Before each use I check the oil. I run Mobile 1 5W30 synthetic in it. I've noticed that if I use the machine for an hour or two of average work, the next day when I check the oil, it's down on the dipstick by about 1/8". Every time. I initially thought it was break-in oil consumption but now the engine has 35+ hours on it. So, that's not an excuse.. Then added ...Over the years, I've operated two ten h.p. Tecumseh L head engines on Craftsman snow throwers. The oil level never varied from day to day use. I used conventional 10W30 in those machines.
Try 10w-30 and see what happens. Or the Amsoil straight 30 10w30 .

 

[Colt45ws]

Or 0W30 GC. Thats what I put in ours.

 

[outshined]

FWIW....Last summer I had a 3/4 full bottle of M1 5w-30 that I put in a 2 year old 5hp Briggs lawn mower. On start up it became a great mosquito killer..smoked like a freight train (it wasn't over filled). So I went back to straight 30 weight. No smoking and very little burn off since.

 

[gomes512]

I think our craftsman mower manual had warned of increased oil consumption using multigrades such as 5w-30. I've run straight30 with very little consumption. I recently started using 10w-30 and it also gave no problems.

 

[Bror Jace]

I don't follow the oil blends as closely as I did years ago ... but is Mobil 1 still formulated a bit on the thin side in each grade? Assuming that's the case, I would expect that has a lot to do with the consumption you are seeing.

Obviously, switching to a different oil (different brand 5W-30 or a 10W-30, 5W-40, etc ...) might improve the situation.

Also, using a top oil will likely reduce consumption ... a 2-cycle oil at around 200:1, MMO, Lucas UCL, etc ... I used to use one of these at least every other tankful when I ran Dad's OPE ... including 2 snowblowers. I would run this stuff EVERY tankful for the first 10-12 hours during break-in.

I'm bothered by engines that consume even modest amounts of oil. It is not really a problem ... just an anal-retentive thing, I suspect.

 

[CSM746]

I have this engine on a 2009 John Deere thrower. I changed the factory oil to M-1 5W-30 High Mileage at about 3 hours on the engine. The factory oil had a lot of glitter in it. I have about 20 hours now with no usage. High Mileage is formulated a little thicker with more ZDDP. These engines start at full throttle and that dictates the need for thinner oil-5W so the slinger can sling when temperatures hover around zero F. You may try the high mileage to see if it helps...and there may be some break in still taking place??? I keep expecting it to suddenly use some, but I will be changing it out shortly as the season is ending.

 

[boraticus]

I'm certain the engine is fine. There is no visible smoke coming from the exhaust and power is great. I suspect that the oil might be vaporizing a bit and being fed out of the crank case vent into the air intake.

Next oil change, I'll try the high mileage formula. I doubt that there is much break in going on with over 35 hours on the engine.

 

[Bror Jace]

boraticus, you may know that I'm a stickler for 'proper' break-in ... even on OPE engines. Following my break-in regimen of modest runs, frequent initial oil changes and use of top-oil, I have never had an engine consume oil between changes.

However, I have never had one of these engines, either.

Is this machine stored outside or in an unheated garage? I'd be concerned about going too thick ... but even a 10W-30 synthetic is probably fine at very low temps.

If it is in a space that does not go below freezing, I'd skip the synthetics and use a mineral oil ... probably 10W-30 or 10W-40 and change it once or twice per year.