B&S 675 Oil consumption

[Nick R]

This is interesting. We have a coming up on 4 year old Craftsman 22" Lawnmower with a Briggs & Stratton 675 series engine. I average 20-25 hours per season, so we'll be looking at about 100 hours by the end of this year. I ran it for the first season on the FF, the next season got Castrol Syntec Blend 10W-40, next season got QSUD 5w30, and this season got Havoline DS 10W-30. It has always burned some oil, no matter what oil has been in it.

In the first 20 hours this season, it burned about 8oz of oil (It took 8oz to fill it back to the fill ine) It smokes lightly on cold starting ( you can only see it with light from the right angle) and it smokes a bit on hot shutdown, the last few revolutions before it stops.

The muffler grate is a bit more brown than other engines I've seen of this age and older.

It runs perfectly, always starts on the first pull. Why would it always be burning oil? It's not horrible consumption, but it's enough to be slightly annoying. Suggestions?

 

[NHGUY]

A lot of B&S engines are made in China,and have been for 10 years or more now....sadly,quality has suffered.

 

[Nick R]

Originally Posted By: NHGUY
A lot of B&S engines are made in China,and have been for 10 years or more now....sadly,quality has suffered.


Mine says "Made in USA" in 3 different places on the engine itself, so mine isn't one of them.

 

[Quattro Pete]

Have you tried running straight 30 oil in it? That's what I've been running in my Toro mower with the B&S 675 engine and the oil consumption is negligible.

 

[Nick R]

I would, but sometimes I have to use it for leaves into December, and start it in the 30s. I didn't care for how hard it was to start late in the first season with the FF 30wt. I'm considering getting some Rotella for the next year.

 

[boraticus]

Eight oz. in twenty hours in a small engine is substantial. I've got a 305cc B&S Kool Bore engine that likes to use oil. The engine was broken in with a decent quality conventional oil then I put in Mobil 1 5W30 after the five hour oil dump. The oil was being consumed at a negligible rate if checked after each use. However, the accumulative effect indicated that it was using approx. 1 oz. or so every three or four hours of hard use. I switched to conventional Castrol 5W30 high mileage and it slowed consumption down a bit but not completely.

Funny thing is that I had previously owned two 10 h.p. Tecumseh L-head engines for ten years apiece and neither of them used any oil. I could go through an entire season and not add oil. Those Tecumseh engines may have been archaic and a bit rough around the edges but they seemed better built than the B&S Kool Bore engine. I will say, however, that the B&S is noticeably more powerful, mechanically quieter and smoother. It eats oil and I'll just live with that fact. I'm curious to see if it holds up as well as the old Tecumseh engines did. Both of them outlasted the Craftsman snow blowers they were mounted on.

 

[tomcat27]

I agree. use 30wt. if you want to make it easier to start, run 5w30 in it from october thru april and run 30wt from may - sept.

 

[Merkava_4]

You can cure that oil consumption by installing the chrome ring kit. No honing necessary.

 

[FowVay]

I would ensure the air filter is clean (new) and at temperatures above freezing I'd use a mono-grade 30. Below freezing (if it's your snow thrower) I'd use a synthetic 5w30.

This has worked for me for many years. I once had a two cylinder Briggs engine that worked great until I did a oil change. I put Amsoil 5w30 in it (I sold Amsoil at the time) and the thing started smoking like a tire fire on start-up. Consumption was measureable during operation. I went back to monograde 30 and it still took two seasons for the start-up smoking to stop. But, it did stop and consumption went back to practically nil.

I think these air cooled antiquated engines just subscribe to a different philosophy.

 

[boraticus]

Originally Posted By: Merkava_4
You can cure that oil consumption by installing the chrome ring kit. No honing necessary.


Thanks for the tip. Do you think an engine with less than 100 hours on it needs new rings? Compression is excellent.

I plan on letting mine run as is. It's not all that bad. If it gets ridiculous or lets go, I'll cure it by putting an new Honda GX340 on it.

 

[kozanoglu]

Originally Posted By: Nick R
This is interesting. We have a coming up on 4 year old Craftsman 22" Lawnmower with a Briggs & Stratton 675 series engine. I average 20-25 hours per season, so we'll be looking at about 100 hours by the end of this year. I ran it for the first season on the FF, the next season got Castrol Syntec Blend 10W-40, next season got QSUD 5w30, and this season got Havoline DS 10W-30. It has always burned some oil, no matter what oil has been in it.

In the first 20 hours this season, it burned about 8oz of oil (It took 8oz to fill it back to the fill ine) It smokes lightly on cold starting ( you can only see it with light from the right angle) and it smokes a bit on hot shutdown, the last few revolutions before it stops.

The muffler grate is a bit more brown than other engines I've seen of this age and older.

It runs perfectly, always starts on the first pull. Why would it always be burning oil? It's not horrible consumption, but it's enough to be slightly annoying. Suggestions?


Nick R, the manual states a 30W detergent oil as the oil to use as far as I remember.It also says if you use multi-grade oils it will consume oil.

 

[Nick R]

Originally Posted By: kozanoglu
Originally Posted By: Nick R
This is interesting. We have a coming up on 4 year old Craftsman 22" Lawnmower with a Briggs & Stratton 675 series engine. I average 20-25 hours per season, so we'll be looking at about 100 hours by the end of this year. I ran it for the first season on the FF, the next season got Castrol Syntec Blend 10W-40, next season got QSUD 5w30, and this season got Havoline DS 10W-30. It has always burned some oil, no matter what oil has been in it.

In the first 20 hours this season, it burned about 8oz of oil (It took 8oz to fill it back to the fill ine) It smokes lightly on cold starting ( you can only see it with light from the right angle) and it smokes a bit on hot shutdown, the last few revolutions before it stops.

The muffler grate is a bit more brown than other engines I've seen of this age and older.

It runs perfectly, always starts on the first pull. Why would it always be burning oil? It's not horrible consumption, but it's enough to be slightly annoying. Suggestions?


Nick R, the manual states a 30W detergent oil as the oil to use as far as I remember.It also says if you use multi-grade oils it will consume oil.


It also says that synthetic 5w30 can be used at any temperature.

 

[troyb43]

Have you tried the Amsoil ASE? This is a straight 30 weight that also gets 10W rating. It works well in my equipment without smoke or oil burning and starts well even in cool weather. It has a pour point of -38F, which should make it usable to -18F. I hope you will not be starting your mower in tempratures that extreme.

 

[TFB1]

Originally Posted By: Nick R


In the first 20 hours this season, it burned about 8oz of oil (It took 8oz to fill it back to the fill ine)


After running a old B&S 3.5Hp that used that much oil per cutting(approx a hour), I'd be thrilled with something I didn't have to add oil every time I gassed it up...

 

[hemitom]

I had the the same engine on a craftsmans as well i put between 40 and 50 hours each year on it from cutting grass to bagging and mulching leaves as well, i ran castrol 15w40 in mine to temps below freezing never any hard starting issue's and no consumption issue's in this time frame at all. Oil still was nice and clear when changed as well. The only thing on mine was a slight exhaust pop almost like a miss it drove me crazy. Now i have a honda gcv 160 it does not run any better than the briggs did, its a quieter running engine and much more fuel efficient though.

 

[Nick R]

I picked up a quart of Shell Rotella T6 Synthetic 5W-40 today at wally world, and I plan on using that. Hopefully that will slow down or eliminate the consumption.

 

[boraticus]

Originally Posted By: Nick R
I picked up a quart of Shell Rotella T6 Synthetic 5W-40 today at wally world, and I plan on using that. Hopefully that will slow down or eliminate the consumption.


Don't bet on it.

Sometimes synthetic oil is worse for consumption.

 

[Joe72Mart]

I picked up a B&S Quantum 6.75 from BIL. 5yrs old, he seldom checked oil, let alone change it. Smoked like crazy when he gave it to me. Used a lot of oil. Put some Kreen in it along with PYB and changed oil 2-3 times. Ran straight 30weight still smoked badly. Went to M1 V-Twin 20w-50. Still smokes a little but oil consumption went way down. M1 V Twin costly, but cheaper than a new Toro. Used it this past season, puffs a little under load, but the Toro Personal Pace mower is great compared to my 25 yr old Lawnboy.

 

[greenaccord02]

Nick, if that doesn't get it I'd get a bottle of Castrol HD-40 and try that. Who cares if it's hard to start in the cold? 20W-50 would be another good option.

 

[Bror Jace]

Having lived in Saratoga county for well over a decade, I can sympathize with Nick R's concern about cold starts. Straight weights (30, 40, etc...) simply don't work well this far north in engines that need to be started year-round.

The Rotella might be an improvement ... but I wouldn't bet a lot on it. Even if if does help (say, by cleaning up a sticking ring or two) it will take a while, probably a full season, before you see any benefit.

Best bet would be to use one of the High Mileage oils, maybe in 10W-40 or 10W-30. Check the pour point of the Max Life synthetics to see if they offer an advantage over the conventional oils.

Another thing you could do while trying the Rotella is to use a top oil/lube of some kind. Either MMO or Lucas UCL are relatively cheap. I'm not sure why this works, but it did on an Escort I had back in the 80s. I think it changes the way the ring(s) react against the cylinder wall, allowing for better sealing.