By Brett Bonner on Unrecorded Date: Edit

Well, after 4 years of sometimes abuse, the engine is finally done in.

My daughter was driving the MaxIV when it died. She drove home with the vehicle with it producing significantly less power. She relayed that something really bad seemed to happen. However, it ran quite smooth, but far less power. It would do about 8 mph max. I even drove it a bit after she made it back.

After getting it home, I checked the ignition and it was fine. One cylinder was definitely dead. Then I ran a compression check. 150PSI in one cylinder, 0 in the other. There is no way that could not be a bad sign.

Upon disassembly, I first found the Gerber screwdriver part I dropped. It was in the alternator. There it had lodged after chewing up the stator and flywheel. The screwdriver part had even damaged the front of the block. The alternator as a whole was still charging the battery after all of this significant damage.

The most amazing thing is that after I took the crankcase apart, the major damage became apparent. First it threw a rod. The rod cracked demolished one of the V-Twin's cylinder walls. The crank was scored. The bearing had seized to the crank and the rod end came apart. The piston still looked good. The heads looked good.

Most amazingly, the CAM SHAFT was broken in two. It was broken in two between the timing gear and the cam lobes. I guess the metal got up there jammed the cam, and snapped the shaft. But somehow, the jagged ends, pressed together by the block allowed the engine to keep running. No kidding, there was at least 3#'s of fragmented and chunk metal in the crank case, a broken cam shaft, and it still ran.

However, I don't think this is a durable engine. The machine was rolled once and submerged once. In both cases, the oil and filter was changed. One time, I had to winch it up at about 90 degrees and had to keep the engine running to help power the winch. After this "winching" experience, the engine froze. I broke it loose, changed oil, and continued to use the machine. Shortly after this last oil change, the engined failed.

I've ordered a new 18HP engine. I couldn't find a higher horsepower engine at a reasonable price. I do have a lot of extra parts now and may experiment with stiffer springs and stronger retainers, mufflers, etc. We will see.

By david berger (Davidrrrd) on Unrecorded Date: Edit

brett b, going with better springs and retainers is a great idea but why stop there, the con,rod and pushrods are week too, best to stop by www.600raceing.com and look for a rev kit for your new briggs 18hp, or get a new crank shaft + rev kit and 1 new cylinder, whitchever,
you will find your new engine will stay together even if you bypass your govener and use the powerband right up to 6000rpm.
but nothing will hold a lawn mower engine together that was runn at 90* angle for any long lenth of time, we must respect the oil sump in a 4 strok is there for lubrication of engine and when at bad angle you might as well have no oil in it at all, if your winch wont runn have a come along with you.

By Brett Bonner on Unrecorded Date: Edit

David - thanks for the tip. No signs of lubrication failure on close inspection. Everything is clean and not discolored. Obviously, it didn't help and your caution is warrented. A comealong is a good idea. Can't count on batteries all the time.

I couldn't find any links for a rev kit at the web site you quoted. It seems to just be a directory. Can you give me the real site.

Also, what is "shimming the springs."

Since the heads are in great shape, I think I may start there with porting, springs, and all. Maybe try to improve the carb a bit and a much better, but quiter exhaust.

By david berger (Davidrrrd) on Unrecorded Date: Edit

timothy@acol.com has done the rev kit in his maxIV,
e-mail him for that info, he can tell you wich links is good. i herd about 600 raceing from him.
one part of the rev kit is shims you slide under the springs to make them tighter, but you shouldent unless you do the kit, the pushrods are week, the retainers are also week, you could cause a valve train failure.
the kit replaces all week components.
tim okeefe tryed a super trap exaust, it is adjustable for sound and power, (how many disc's you use)

By Chris Wetteland (Wetdawger) on Unrecorded Date: Edit

Brett what should the compression be in each cylinder for a working engine. I dropped a bolt between the flywheel and block and did some breaking of my own.

By BrettBonner ( - 199.82.243.73) on Unrecorded Date: Edit

It's based on the difference of the cylinders. A difference of 20% is a bad engine. In my case, my good cylinder was 150PSI under typical test conditions (good battery, no plugs, wide open throttle) and 0 in the other. No need to do the math in that situation unfortunately.

With the new engine and a new stiff belt, the machine is very peppy now. The replacement was an un-goverened engine with no recoil starter. It cost $850. It went in fine EXCEPT that the base mounting needed larger holes and I have had to fab some parts for the throttle as the MAX throttle is set up to use the governor shaft and this has no shaft.

However, I'm not sure if the engine or the new drive belt by Gates from Napa is the biggest reason for the increased pep and speed.

By Fred Sowerwine, Montana's Max dealer (Fred4dot) on Unrecorded Date: Edit

Brett, did you pick up some liquid belt dressing from NAPA when you got your new belt? If you will use a little on the belt edges every time you change your oil, you will get much improved belt life and always excellent belt performance.

By David Keeso (Argomag) on Unrecorded Date: Edit

Fred, i have seen you post other comments on using belt dressing in these machines. is this on the drive belt between the driven and drive clutches? (drive belt?) How does this stuff work and what difference does it make. If a belt is very tight but at high speeds does't engage fully, would that be a result of the belt slipping? What i mean, in the ARGO, i can get it up to 3/4 throttle no problem but it takes a while to get right up to full throttle, the engine sounds like its revving as high as it usually goes, but it doesn't run as fast. If I keep up on the throttle, it will get to full throttle eventually and after its been running for an hour or so, everything runs fine- gets up to speed fast and smoothly.

By Fred Sowerwine, Montana's Max dealer (Fred4dot) on Unrecorded Date: Edit

David, yes, it is on the rubber/fiber drive belt that connects the drive and driven pulleys. Belt dressing impregnates the belt and gives better grip discouraging belt slip hence giving longer belt life.

Sounds to me like your drive pulley might need to be serviced. Put your tranny in neutral and watch the pulleys when you rev up the engine. If your belt doesn't go to the outer edge of the drive pulley (or close to it) as you reach full throttle, it isn't opening right. Could be your drive belt is worn and narrower that it should be. Could also be that the outer edges of your belt are glazed just a little and not getting a good grip.

Try the belt dressing, it will give life to an old belt, but the real benefit is on a new (or newish) belt because it will keep it new longer. For a few cents an application, you can make that $45 belt last about 33% longer.

By liflod (Liflod) on Unrecorded Date: Edit

At Copper Ridge, John Hoath was showing me how to adjust the driven clutch to improve low end torque. Maybe he can chime in and give an explanation to give your Argo a little more low end.

By Jon Hoath on Unrecorded Date: Edit

liflod,
More than happy to.
I take 2 washers/spacers out from between the two clutch faces and put them on the side of the snap ring. this makes the belt ride higher on the clutch faces and hence gives you a granny gear.
Note, I also wind the spring one extra turn also when reassembling the clutch.
As for the drive clutch on the motor, I have not experemented with that yet, basically because the driven clutch change has been good enough to make the difference necessary to keep me happy, so far.. Just use cation when taking the driven clutch apart, it is under alot of tension from the spring. Use C-clamps, a large bench vice, or best yet a shop press.

By David Keeso (Argomag) on Unrecorded Date: Edit

Fred, thanks for the info. My belt is fairly new- was replaced when it went down to ODG to get overhauled. Its only had about 20 hours on it since.

By Rogersmith (Rogersmith) on Unrecorded Date: Edit

David, besides all the other advice, lube your clutches, the shaft and sliding surfaces, also the three plastic buttons on the driven clutch. Assuming your magnum is like my response.

Jon, that's interesting, I've adjusted my driven clutch spring.. it had about 7 index holes. But I havn't played with the shims.

I figured out a drive clutch mod, adding a spacer to let the shivs close tighter, ie higher geared at the top but still same low gear. My belt didn't ride at the top of the engine clutch, it was down inside about a 1/4 inch. Now it's at the edge. I'll get it apart sometime and measure the shim I made.

By argomag on Unrecorded Date: Edit

roger smith- what plastic butttons? I have never seen these, then again, i never really looked either. what is the best lube to use on the clutches?

By Rogersmith (Rogersmith) on Unrecorded Date: Edit

Argomag, I called them plastic buttons but that's not the right terminology. And I've only worked on one cvt, the one in a 98 argo.

Alright, got the parts manual out.. the buttons are called "cam shoes". hehe

The pulley half that slides has ramps, or cams, and there's a mating part they call a cam, they fit together. The ramps/cams handle all the power that goes through the cvt. As the driven clutch open and closes, it's sliding on the ramps/cams. The pulley has three non metal cam shoe inserts and they ride on the mating part, keeping the metal to metal cams slightly apart.

I don't know what the best lube is. ODG says silicone spray on all the clutch parts. I've used powdered graphite which works good, harder to apply.