Sawmill Engine Life

Small motors last a few thousand hours on average, but careful maintenance can stretch their useful life. October 14, 2006

Question
When looking at used portable sawmills on line I've noticed the vast majority have engine repairs or replacements at or about 1500 hrs or less. Is this normal? What life expectancy should I expect out of a 28-35 hp gas engine? I'm interested in getting into custom sawmilling but don't want to be replacing engines every 3 years.

Forum Responses
(Sawing and Drying Forum)
From contributor A:
Caterpillar motors are guarantee for 3000 hours.


From contributor B:
That's the nature of the beast. All that sawdust the engine sucks in is tough on it. I had a gas mill for 8 years and put three 24 hp Onans on it during that time. I didn't have an hour meter on it but would guess that to be about every 2500 hours.

From contributor C:
I had 4600 hrs on mine before I had to replace it. I had a 20 hp Onan and I keep up on the maintenance because of the sawdust. I always changed the air filter and the foam ring every 50 hrs when I changed the oil.

From the original questioner:
Thanks for the education - none of the companies I contacted gave me a straight answer. How do you make any money at custom sawing? Sounds more like $75 - $100 of every job would have to go toward maintenance, engine repair or replacement plus gas, oil, etc. I don't see where the profit lies?

From contributor D:
I have been running synthetic oil in the many small engines on the farm. This has increased their life greatly. You should only use it after the break-in period of 50 to 100 hours to give the rings time to seat. I have also at times reduced my Timberking B-20 mills rpms on soft woods from 3800 to 2400 and could not tell much difference. The mill has a 27 hp Kohler for the blade and a Briggs for the hyd. The Briggs runs the mill super at 1/2 throttle and loads 28 inch diameter logs. Wide open is not always best and reduced rpms save engine life. I also change oil at 1/2 the hours recommended. The air cooled engines run at higher temp which causes the viscosity to break down faster and you can not see this by just looking at it. So I take no chances with my engines. I know a lot of people think this is a waste of money but we do not replace engines every few hours.

From contributor E:
If you take an engine life of 2,500 hours, and a cost of about $2,500, then that’s only $1 per hour to pay for a complete replacement after it wears out. Spending another $1 an hour on proper maintenance and good quality oil will hopefully extend the life too, so that’s a good investment. You could get a better quality engine, but is a $6,000 engine that will run 6,000 hours actually a better investment? You have to calculate engine maintenance and replacement into your cost, but blades, fuel, mill payments are probably the bigger costs.

From contributor F:
Anytime you operate equipment that can wear out, or has maintenance issue, a reserve amount should always be set aside, or at least noted, so it won't be a shock. Lots of mill owners make decent money custom sawing, but they have to allow for the blades, or sharpening, fuel, oil, and of course, wear and tear. If you were sawing for $50 an hour, setting aside $3 for every hour used would fund a new motor when it is needed or a mill upgrade and your old mill will not lose a lot of value.

From contributor G:
I have a 35 hp Wisconsin on my Woodmizer LT40 super - it has over 2,032 hours and is still real strong. Wisconsin has a good reputation for longevity.

From contributor H:
My Onan 24 hp on my mill has 5500 hours – it might blow tomorrow, but runs good today! At 1500 hours something happened to the original motor and it was replaced under warranty, and now the mill is a few hours shy of 7000 hours. The man I bought it from kept it serviced regularly.

From contributor I:
My mill was made in 1997 and still has the original Deutz diesel engine on it. It doesn't have an hour meter on it. I bought it used off of a guy who ran it as a commercial mill.

From contributor J:
I have been running the Kohler 27 hp for 18 months now and been very pleased. The heavy duty air filter is the best air cleaner I have ever encountered on any small engine. I check it regularly and it has never needed any real attention on the first stage of the filter, much less the second stage.

From contributor K:
My 16 hp Vanguard on my Lucas just gave out. It has been burning oil the last 6-9 months, but no complaints. It probably was a freak engine but I got just around 10,000 hours from it. If the new one does half as well, I’ll be happy. I was wondering if it was ever going to die. I have a new one on order for $1,250 – that’s with clutch assembly - or .125 cents/hr.

From contributor L:
Talk about a crap shoot. Some go and some blow! A little effort to try and maintain an engine can go a long way or it might not make a bit of difference. But some things that should help are as follows.
Oil topped off and changed is a start
Air cleaners kept clean
Cooling fins kept clean
Maintain proper air flow around engine
Fuel system kept clean

Proper and quality fuel
Warm up for a few before full load
Cool down before shut down
Run at proper RPMs
Maintain the device being driven to reduce engine load
Pay attention to performance while in use
Bigger is better!
Read the manual!

If you engine is over max load for more than 50% of its life, it is too small. Think upgrade if it is an easy fit and think rebuild if it is feasible and not too late. None of us are angels when it comes to doing the right things all of the time, but the more we do them, the closer we get to eternal engine life. 1,500 hours seems weak to me. 3,500 to 5,000 seem more in order and I would hope for more. Attitude plays a big part in things too. Some want to squeeze every penny out of things while others expect and plan for early replacement.


From the original questioner:
I have decided to buy a mill thanks to the advice in this forum. I've decided on Orange -any pros or cons? Is the new 28 hp Kohler FI adequate for custom sawing or should I move up to a 33 hp diesel?

From contributor M:
I chose the 28 hp (air cooled/ gasoline) engine. The alternative was heavier and more expensive. The other mills I ran did just fine with the 28 hp as well.
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