'01 Suzuki King Quad 300 - Won't start but has spark

[wiktoriatopajew]

The choke should be up and forwards for warm running.

You should change the fuel. Stale fuel causes all sorts of problems.

It probably won't run right without the air filter.

Edited May 12, 2023 by wiktoriatopajew

[Mech]

I wouldn't worry about the fuel that gets drawn during the compression test, that always happens and causes no problems. I would definitely run the motor till it was warm to get the marvel stuff out. It's best to do a compression test with the engine warm anyway.

The plug sure looks like it's burning oil, I think I even got a whiff of burnt oil from here.. 

It's entirely possible that the compression rings, and compression, can be fine, but an engine still burns oil because the oil rings are gummed up and stuck in their grooves. Likewise, an engine can have broken compression rings yet the oil rings be fine and so despite low compression they have no smoke or oil burning. In the normal run of things both set of rings wear out pretty much together, but there are things that go wrong that bugger up only one set of rings or the other.

I think in this case I'd just pull the head and barrel and check the crank and rod for wear or damage, then fit rings and valve seals, and a piston if needed, and lap the valves and then it should last until the next set of rings when it would probably be time for an entire overhaul..  Engines will usually use a couple of sets of rings before they need a crank..

Edited May 12, 2023 by Mech

[Gwbarm]

My thoughts were the fuel might cause an inaccurate compression reading, but maybe not, I would try a new plug and see how quickly it gets black from running it, black can be a combination of oil burning and running rich.

[Mech]

We do compression tests all the time without worrying about the fuel, not on old machines anyway..

You're right about the blackness and the wet look, but all those little bumps of burnt oil didn't get on there in a hurry I don't think..

If it was mine I'd keep riding it because oil's cheap and I'd hope to leave it till it was time to do some other work. But, it's been for a few rides and seems to me it's probably not going to get much better, so if Rambler is wanting it good I think a set of rings and valve guides is what's needed.

The rest of it seems ok eh Rambler ? Gears and clutches seem ok, drive line and chassis is worth it ?

[unirambler]

Well, I cleaned the plug to see if it got black very quickly but it really didn't in the ~10 minutes I ran it to warm it up. It still seems to me that the longer I run it, the thicker the smoke coming out is. 

Anyway, I tried the compression test. It looks to be reading low - about 123psi - though I tried it multiple times and one time it read 150 but the rest were 123. I tried putting in some oil and it didn't seem to really change - might have gone up to around 125 or 126. The manual says it should be 142-199 and the lower limit is 114.

So, I am going to do as you suggested, Mech, and pull the head and barrel and go from there.

🙂 What timing! As I was typing the above, you just replied again. I am not really sure about the drive line. Everything seems to work but it definitely has drag but that could be the brakes. The clutch sometimes seems that it may be slipping and then seems to grab, but sometimes it seems to work fine. Once in a while, it will rev up but not really move and then suddenly take off - mostly it seems to happen if I am trying to turn sharply. I haven't checked the transmission fluids yet though. I am planning on getting it jacked up and going over the drive train now that it is running. I will probably do that before rebuilding the top end so I know whether it will be worth it.

I wouldn't mind running it with the burning of oil but it really puts out a lot of smoke. My neighbors don't really appreciate having to close their windows when I ride by. 😉 

[Mech]

haha..  Ya gotta have fun.

[Mech]

When you are pulling that barrel off, lift it a little, then, before the piston comes out, wrap clean rags around the con rod blocking the hole into the crank..  If there's bits of broken ring in there you don't want then dropping into the sump.. complicating things..

[Gwbarm]

Oil is cheap but smoke is annoying, probably good to go ahead and check it out, if its smoking that much something is definitely wrong. 123 is not that bad compression wise, iv run some with less than that that didn't smoke, probably one of your rings is stuck and might pop back out after running it for a while, but if the ring is broken that's not a good thing to do. Does the smoke get worse or better the longer you run it.

[unirambler]

I would say that the smoke gets worse - thicker and cloudier - the warmer the engine gets. But I don't think it is any worse than when I first got it running. It may be a little better - or I am just driving faster so I don't see it as much!

[Gwbarm]

It does sound like you have a stuck or broken ring, the only other thing I might try before teardown is pour some carb cleaner into the combustion chamber so the rings get soaked with it, helps remove varnish and crust sticking the rings to the piston, I use pretty strong stuff Berryman Chemtool. The only problem with that is that it does seep through and dilute your oil some. Sometimes it works, sometimes it doesnt, then pull the jug.