"Rainbow" Tractor


Old 05-03-14, 03:52 PM
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"Rainbow" Tractor

The is what the owner of the local power equipment store called my yard tractor that I got snookered on my a local old guy. (Damn those old guys!!) Snookered because I paid $500 for it. Grrrrrrrr

According the to underside of the seat it an an MTD 13A4662F129. The body armour on it calls itself a yardman 18HP lawn tractor whereas the engine is a B&S 14.5HP OHV I/C quiet 287707 with a 42 inch "G" deck 13AR608G022. A complete rebuild of everything.

This is my third season with it. First season had to replace the fuel line and filter. Had little issues with it that I don't remember what they were. Last year I had to replace all the belts. A fiasco due to being a "rainbow" tractor. The pulley for the drive and the PTO belt literally fell off last year, one of the many issues last year.

Anywho, this year I have to replace the flywheel as it is missing a few teeth. I can get it started but I have to manually position the flywheel so that the starter thing can catch. Hey, it works for the moment.

Today, after it sitting all winter I did get it started very quickly and other than positioning the flywheel, no problem. Hey I even mowed the lawn!

Besides the flywheel other issues carrying over from last year presented.

The PTO belt is loose. Per the store (mentioned above) I put on the recommended belts. When mowing, the deck just doesn't seem to have the power it should...duh, the belt is loose. Also between the two blades it mows unevenly.

While common sense tells me that I need to make adjustments to the deck, it also tells me that despite manufacturers recommendations the PTO belt is too big.

Today with the deck at its highest position the blades sounded strong and powerful. When I lowered the deck to 3" the blades pretty much STOPPED. WTH???? I was on my concrete driveway when this occurred so it was not due to trying to mow high grass. There was nothing to put any strain on the blades.

OK so my main question at the moment is regarding the loose belt. There is no doubt that I have it on and around the pulleys correctly. With the engine off if I engage the PTO lever, the belt is obviously loose.

Something just ain't right.

Would getting a smaller PTO belt be out of the question? I'm thinking of doing the string measure around the pulleys for a measurement???

Am I far off track here??

Thoughts?? Questions?? Opinions (be kind)???? Inspiration!!!????

For this lawn tractor I also have a grass catcher that gets clogged more often than not but I think that is due to the lack of power to the blades because of the apparently lose belt. I lawn sweeper that I got last year but admittedly haven't used it yet and an aerator.

Help me out men!! (Oh and I'm still working on the tiller)
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Old 05-03-14, 04:20 PM
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Since it is a "Rainbow" you may have a mix/match of pulleys. Possibly the pulleys are grooved for a 5/8" belt and your current belt is a 1/2" one. This will play heck with power transfer to the blades. Then again your pulleys may be worn out and do not have enough taper left to grip a belt. See if bottom of pulley groove is shiny from belt bottoming out in pulley.
So many possibilities.
If the pulleys check out, then you could take the too long belt for comparison and get a belt some shorter. You could try to determine just how much shorter by engaging deck and checking excess slack.

Good Luck!

Old 05-04-14, 05:35 AM
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I'm just a Real Estate Broker; but I have a few lawn tractors and other equipment around here to help challenge my mental stability when people alone don't do it.

So you've got a bit of both: the idiosyncracies of the tractor; AND the un-documented re-engineering done by the prior Owner.

One of my tractors (mowers) is an MTD, and I can say that it seems to be far more temperamental regarding belt length than anything else. The MTD doesn't have an idler pulley that can be used to adjust for slight variations in the belt length. You probably have to rely on the lowering of the Deck to provide tension on the Deck Belt . . . . unless you can see some kind of adjustment mechanism.

If it's true that the Deck is slightly smaller than the chassis was originally designed to accomodate, then it's probably true that you need a belt which is larger than what the Deck called for; but smaller than what the chassis would call for. You'd almost have to engage in some trigonometry calculations to get this precise, and then still want to field test your results.

Larger pulleys can compensate for a shorter belt, and vice versa; but the pulleys on the deck spindles are pretty much a given, and the Drive Pulleys (sheave) on the engine are sold in predetermined siamese pairs . . . . so you're left with testing your patience and having to do a bit of trial like the Rooster suggested.

At least, it sounds like you are dealing with a Shop where they are a mite sympathetic to your plight, and may allow you to try several different sized belts until you identify what is now the correct length; provided you can return them un-damaged. Also check to make sure the deck's belt guides are properly mounted and allow clearance for the belt's passage. And those MTD suspenders that hold the deck in position can often get mis-aligned when being installed, often with a clip being put on the wrong side of the deck suspender . . . . or completely missing.

Keep good notes, so that you'll have something to refer to, and not ever have to learn this all over again.
Old 05-07-14, 08:41 AM
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Howdy folks.

Still trying to get the flywheel off. Sucker is on there like it was welded in place.

On the belt issue. the belt best recommended by the shop/manual is a 60" 5/8" v-belt. There is tons of slack and the blades will not move when engaged unless the cutting height is at 4 inches or higher. WTH??? Anyway I went out and got a new belt but a little smaller. My selection at TSC was somewhat limited with no B&S belts in the size range that I wanted so I got a Huskie brand 1/2" 58" belt.

Now the 58" belt has the blades running whether engaged or not, ok I get it that belt size is too small even though I have little to no blade movement with a 60". Is the 1/8" width difference enough to make that much of a difference? I'm wondering if the pulleys underneath are as mismatched as the rest of this beast?

Until I get this flywheel pulled I can do no more with the deck though except pull it off and give it an extra good cleaning.

Any tips of flywheel removal? I've seen tons of Youtube videos and pages and pages with instructions but none of them are working. This flywheel is held in with a bolt and I am using the official and specific B&S flywheel puller.

Thanks in advance.
Old 05-07-14, 01:08 PM
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I can't help you with the flywheel problem but I can shed some light on the belt problem. When you went to the 1/2 inch belt and downsized the length by 2 inches it caused the problem of not disengaging. I would strongly recommend that you stay with the 5/8 inch width and downsize a maximum of only 1 inch, a 1/2 inch shorter belt may work perfectly. You may need to go to an industrial belt supplier to get the proper belt. Belt-slipping "clutches" are notorious for needing an exact size for proper operation. You may also need to look at the guards that hold the belt close to the pulleys when in the disengaged position. If there are no such guards then you may need to fabricate them.
Old 05-07-14, 04:04 PM
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For the flywheel, if the proper puller fails you can try backing off the center bolt a turn and give it a sharp wrap with a hammer. You can also try cranking the puller down hard and give it's center a whack with the hammer. I've also had luck once putting a riveting gun on the end of the bolt to pound/vibrate it free. With whatever you try start at lower force levels and work up. I would avoid any kind of prying behind the flywheel as there's a chance you might bend the crank. Unfortunately it's a tight fit when shiny and new. Any corrosion can almost lock or weld the pieces together.
Old 05-09-14, 04:34 AM
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In your original Post, you mentioned that just last year you had to replace all of the belts . . . . so at that time, how was the blade belt selected ?

I gather that either last year's "new belt" either stretched as it got broken in, or something else in its path got loosened, and it won't gather traction on the pulleys. Otherwise it never would have worked when installed last year ?

Something must have changed during the year.
Old 05-09-14, 08:22 AM
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OK here is where I stand.

Never got the flywheel off, resigned to continue starting it by manually placing the flywheel past the sheared teeth so that the starter will catch. Doable for now.

The belt. I'm not sure how they figured it out but I brought in all the specs and photos and they ran with it.

I ended up buying a husky brand belt, exact same measurements as the previous belt. I had also taken the deck off to give it a good cleaning. There is a double pulley on the deck and the upper pulley, the one the belt in question goes around is shined to a mirror finish on the inside. I guess when I looked for that a couple of days ago the lighting wasn't sufficient or I just didn't look as good as I thought I did.

Continuing on to the new belt. Despite being the same size as the previous belt there is a very remarkable difference between the two. It seems to me that something is eating away at the width of the belt. The outside of the old belt also has some fraying and something like a burn mark.

I put the new belt on yesterday and mowed the lawn. The top edge of the new belt has some fraying on it.

Vermont, when installed last year it worked but there was a huge difference in the power and how the mower cut. With the new belt this year I can see a huge difference in the cutting.
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