Need help finding correct belt size

[Morbus]

I bought this sitting lawn mower. Its been repainted and tags are lost.

It has a 12hp briggs stratton engine. (Engine codes: 284707 - 0147 01 - 9412234(E) )
It has two knifes measuring 18 inches each.
So its a 12/36 ?

It looks just like this model i have attahed a photo from, only difference is that my battery tray is 90 degrees rotated.

The belt going from the engine to under the variable pulley under the seat has broke. The old belt was really torn up but i measured it to be about 50 inches long. I bought a new belt (754-0370) But its to short, even when I move the pulley all the way up front by putting it in park. Ive usig a rope and installed it between the two pulleys, I measure it to be 54 inches at the closest position.

Before I buy new belts (hard to source in my country, and long delivery times) I want to make sure its the right one.
My googling has lead me to the part number 0754-0280, that belt is 53 inches. Would it still be enough? What happend when i select gear 6 and the pulleys move 4-5 inches longer back? I think I need a longer belt still?

Ive found belt with partnumber 754-0434, it is 58 inches long, but its 1/2 inch wide, not 5/8 like it should be?

Could anyone be so kind to help me figure out my modelnumber, and what belt to look for?

 

[bertsmobile1]

According to the engine serial number your engine was made in 1994 (94) December ( 12) on the 23rd day ( 23 )
According to my aftermarket parts catalogue belt 754-0280 is correct for a 32" MTD mower from 1982 to 1998 with variable drive system.
Note it is not a standard 5/8" B section belt it is a 5L which is shallower , Gates list it as # 6447BR which is a 5L x 53.2" outside length belt

Vari drive belts should always be replaced as a pair.
The corresponding upper ( rear ) belt is 754-0281 ( 5L x 44.05" outside length )

Lots of people will try to sell you a standard 5/8" B section belt that has the same effective length which is wrong , will wear the pulley badly and slip in speed 1 & 6

 

[Morbus]

Wow thanks alot!!
Beeing 1994 36" deck (2 knifes each 18" - I guess thats how they measure deck width?) with 12hp, is it possible to figure out the MTD modelnumber? I`ve not figured out the model number system for pre 1997 models.

I was not aware that the vari belts should be replaced in pairs. The shop I order from list the OEM MTD belt, not a third party. And the price was pretty high ( i think) about $100. So I think the belt is the real deal. They do not have the rear belt though. Will try to sort that from another source.

 

[bertsmobile1]

YEs the blades will be 18 + a little bit 18.5" usually measured diagonally from cutting tip to cutting tip
IF the deck is a side discharge then you have the E deck
Your MTD number should be something like this
135 ? ?6? E ???
SHould be one of these 1995 MTD models with E in the position shown above
There are 2 frame sizes 400 & 600 that were fitted with 12 Hp engines
so 135 ? 46? or 135 ? 66?
The 6 is the number of speed notches can be 4 through to 7
so that will limit your search a bit
The first ? is the engine code and will be a letter A - Z but I don't have a copy of those but one of the dealer techs may be able to fill that in .
Apart from that just flip through all of the E deck models with your number of speeds & find one that looks like yours with a brand name that was sold in your region
With the exception of the hood all the 400 frames use the same parts and all of the 600 frames use the same parts and some will be common to both frame sizes

 

[Morbus]

Its a 6 speed. When following your link i cant find a combination of 400 frame and 6 speed, so it should be a 600 frame I guess.

Im still wondering how the vari belts behave when moving the shifter all down, the pulley slides forward so that it makes it easier to change the front belt, but i really cant seem to wrap my head around that it can move all the way bac again with the belt fitted.. The belt isnt stretchy enough to allow for such a big movement.
Is there a order to replace the two belts? the rear one or the front one first?

 

[Scrubcadet10]

did you look under the seat/ bottom of seat for a model number?

 

[Morbus]

Yeah, nothing there. Its been stripped of all stickers, and repainted..
But I have now checked all the models on jacksmallengines.com now, and im pretty sure it is a 135e470f023. Anyway, the 754-280 belt still comes up, so i have ordered that one aswell.

 

[bertsmobile1]

Just remember all of this is predcated on that being the original engine fitted .
I did run through all of the front tranny belts & 754-0280 is the only one near your measurements .
Remember the variator pulley goes from around 5" diameter to 3" diameter which makes a big difference to the belt tension.
These systems are a tug-o-war between the rear belt & the front belt with your foot becoming the extra man

 

[Fish]

Here it is!!

Grays Australia - Online Retail & Auctions

Grays is an Australian online retail and auction company, offering a huge range of consumer and industrial goods, direct from manufacturers and distributors.

www.graysonline.com

 

[Morbus]

Here it is!!

Grays Australia - Online Retail & Auctions

Grays is an Australian online retail and auction company, offering a huge range of consumer and industrial goods, direct from manufacturers and distributors.

www.graysonline.com

Yes, well thats the same page as i downloaded the image from.
Not the exact same vehicle, as mine has been repainted in blue.