JM 184 Pully questiion.

[garym31931]

Have a Jinma 184 with the yt290 2 cylinder motor. Now the question, when I took the radiator off to replace it, the fan belt was very tight with no adjustment, (had to take the adjustment arm off from the block) to get the belt off, and was pretty frayed. So decided to replace the belt while I was replacing the radiator and fan assembly. Got the new belt and it is even shorter than the one I took off.

I noticed there are 2 pulleys on the crankshaft, the old belt went to the bigger of the 2 pulleys then the water pump, alternator. The larger of the pulleys is about 4 1/2 inches in diameter, but the is a smaller pulley about 3 inches in diameter, which should I be using. The only problem is if I use the smaller pulley things do not seem to line up real well.

Plus this tractor has always been problematic about overheating, having the radiator cooling fins cleaned out helped but it is still easy to overheat it.

So what do I need to do, change to the smaller pulley, or go to NAPA and try to find a belt that is about an inch bigger than the one I took off?

Thanks
Gary

 

[Bob Rooks]

You want to use the larger crankshaft pulley because it will spin the coolant pump faster for better circulation.
Am I to understand correctly that there is no slotted adjusting bar on the alternator? I doubt it, but do you have a spring loaded idler pulley? That would account for being non-adjustable.
In regards to the overheating issue, have you tested/replaced the thermostat? If your engine has high operating hours on it, another cause could be an eroded coolant pump impeller. This can be caused from coolant contaminated with engine casting sand. This is one of the reasons why higher end machinery have coolant filters.

 

[garym31931]

Thanks Bob, there is an adjustment slot in the bracket, but the belt that came with the tractor is so tight that there has never been any adjustment available. When the fan flew apart and ruined the radiator, I had to take the adjustment arm lose at the block just to get the belt off.

Actually I have tried running the tractor without a thermostat and with a brand new one that I tested using water I heated in a pan and watched it open. I used a thermometer and when it opened it was close to the correct rated value.

The tractor has 309 hours, has had regular scheduled maintenance. It has had the coolant replaced at least 2 times, once when I had the radiator off, so the radiator shop could clean it to make use the cooling fins were not plugged. We back flushed the system at that time, we did get a lot of gunk out then. Looked like brown slime.

Thanks for the ideas.
Gary