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318 onan life span?

6034 Views 20 Replies 15 Participants Last post by  flymo
I have a 1983 318 that I just purchased. It says 1040 hours on the meter but has a 1997 onan p220g in it that was put in about 50 hours ago. I am wondering what is the life span on the onan p series engines? I don't think I have read on here of anything over 1600 hours. If you guys have more than that what are you doing to keep them from blowing besides just frequent oil changes. what is the secret?
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Hi Carles - I think the secret to long life on an Onan engine is keeping the cooling fins clean, regular oil and filter changes, keeping the air filters clean, and staying up on adjustments and other issues that need attention.

I have seen posts over the years where claims of 2,000 hours upward of 3,000 hours and still running strong, and I've seen rants where the engine failed at less than 1,000 hours. - Dave
Keep the oil changed, the engine tuned up, valves adjusted and heads decarboned. They will last forever if you do that. Most people dont do the decarbon or the valve adjustments very often unless they see a problem. By then its usually too late.
ok, gotta ask. how do you decarbon the heads & what does the valves set on ? thanks
My .02 cents. everything above especially about air filter and fresh oil and filter.
Also, warm it up good before applying a load. (like mowing or plowing), and cool it down for a couple of minutes before shutting it off.
I think this applies to all engines but it seems that most people have forgotten it because car engines are made so well and last so long.
I usually let it idle while I take the sidewalk blower and blow all the dust off the deck, engine battery, etc. That takes just about long enough then I park it and kill it.
Also keeping all Teenagers (especially boys) away from it will probably add years to its useful life.
1. regular oil changes
2. synthetic oil
3. regular maintenance (filters, adjustments) etc.

synthetic oil has changed everything on engine longevity.
Yeah, I would like to know why decarbon the heads. What if you don't? Do you put new head gaskets on after decarboning? What are the heads torqued to?
I think this is like asking how long my car will last. It ALL depends on maintenance, care, and use.
I would say, dont worry how long it will last , just take care of it the best you can. I have known people that have bought brand new cars that had engines blow after a couple of thousand miles.
All engines are different , even from new. Some may last and some may not, even with the best of care.
To de-carbon a head you must remove the head and scrape all the carbon off . Preferably not using an ice pick, if you get my drift.
I dont know what the head bolt torque is ,but if your going to do it ,you should have a manual anyway.
To me if your going to own a tractor your first investment should be a manual.
Roy is correct. Onan also used to sell a spray that you could spray into the engine while it was running to do the same job. I know someone still makes such a thing, try googling "Decarbon engine spray" and see what that turns up...

As far as what happens, if a chunk breaks off in the cylinder, it can score the cylinder walls or beat up the piston, or get stuck in a valve causing it to stay open and burn, or backfire...none of those are good things!
Easier yet-- don't build carbon. Watch your plugs and keep them tan, not black. Otherwise, the first engine lasted 1000, you can get more out of the second with good maintenance. I'm hard as heck on mine and it's got 1400
Top Engine Cleaner is the stuff to us to clean carbon. You can get it at most GM dealers either in a spray can or a bottle you can pour out of.
Isn't SeaFoam a carbon remover? I know in a pickup it will blow a lot of black smoke if you put it straight in the brake booster. In a Honda engine we fouled a few plugs bc it knock so much carbon loose.
Seafoam smells very much like Top Engine Cleaner but I don't think it is as strong. I am sure either will work, but the Seafoam may take longer.
Cant seem to find the what fits what sheet. But found a blower and hitch, the guy swears it will fit a 425. But want to be sure.Blower is a MO1481xo40060. And with a MOhitch024758. Tnx
Chart is here: http://www.wfmachines.com/discus/messages/96042/400series-96201.pdf

It looks like that's the right blower, and you'll also need the quick hitch, front driveshaft and bearing, and possibly front hydraulic outlets and lockout valve if you don't have them on your tractor already.

It comes with a 024758 quick hitch and drive shafts. (no part number on shafts) But no lock out valve. Got four hydro outlets in the front.
You don't absolutely need the front lockout valve - but it does mean the rockshaft cylinder will have to move through its travel before the chute will start to rotate. It's annoying, but workable.
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