Yanmar GM10

[Biffa_Clark]

Anyone had any problems with altenator belts on Yanmar GM10's. I've two problems with mine:

1. the old belt would slip badly even though it was tightened correctly.

2. I've bought a new one (genuine part from Yanmar) and it's the wrong size - at least 1 inch too big. It's an old model ca. 1990 - has the belt size changed? Has anyone any idea what to buy as a replacement (preferably cheaper than the last one) - will a car one do the trick and if so which one?

Thanks,

Ian

 

[DanTribe]

I have used Halfords fan belts on 1GM and 2GM.They perform just as well as "genuine "parts.
Measure the length of the old belt, the Halfords part number refers to the length in millimeters.Eg HB 440 or whatever. I spent half an hour in the shop measuring all the belts before I twigged that.
Dan

 

[tr7v8]

You need to know the width as well, such as x10 = 10mm, some motor factors have a gauge to size fan belts on. Continuous slippage indicates that the the pulleys are too polished and need a good going over with medium wet & dry.
Sometime spraying WD40 on a slipping belt will give it grip.

Jim
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[vyv_cox]

Belt wear

Belts don't wear evenly. It's quite common for used ones to have very different widths after a season or so. This means that you can set the belt up perfectly in one position but as soon as the engine rotates, the belt goes slack as it rides lower in the Vee. Since finding this out I always assess the wear of belts by checking their width at several points.

 

[dickh]

Not sure wether it is a plain vee belt or the 'Cogged Raw Edge' type. The 'Cogged Raw Edge' type have cut flanks and what looks like internal gear teeth on the inside. This type transmit more power than the traditional vee belt which is a traditional wrapped construction.
I have found the same problem with my Perkins Perama and fitted a slightly smaller belt from a different manufacturer - the perkins part didn't last a season. Try an industrial suppler like Fenner or BSL who have a huge range. I found GATES or MITSUBOSHI belts best, but even so I have to change it every 2 years. I also always carry a spare belt.

dickh
I'd rather be sailing...

 

[jimkirby]

I have an IGM10 which used to eat belts! I think the problem lies in the top attachment of the alternator. This is a long bolt that goes through the casting attached to the motor body. when you tighten the belt the clearance at the top attachment allows the alternator to twist very slightly. This in turn puts the alternator very slightly out of alignment with the drive pulley and hey presto the belt wears.

I supose ideally a very thin sleeve over the bolt would fix it ;what I did was to tighten the belt using a bottle screw betwenn both pulleys to get the tension and then tighten the top bolt fist making sure it was in aligment (by eye)

Since doing that the belt has stayed in tension and there is no more belt dust over the engine box!

I cant help on belt alternatives but if you take the recomended belt to a garage supplier to make sure the V angle is correct they should be able to match to length for you.

JK

 

[Guest]

yes - i had problems with belts on the yanmar, and found that the previous owner had fitted halfords type motor belts. these seemed ok at first, but rapidly started to slip. the problem was that they were the wrong width, so when tight they were sitting on the bottom of the pulley rather than gripped by the sides. since i changed to the correct sizes, no further problems whatsoever.

you can get the belts from fenner power transmissions - a retailer of drive belts etc with branches in most large towns. you might first need to buy the correct yanmar spare to get the measurements on which to buy the pattern belts. in the case of my 2gm i have found that the 13mm by 750mm size fits the alternator, and there is even one to fit the water pump belt, which can get chewed up if the mild steel pump pulley starts to loosen on the pump shaft.

the standard motor spares belts are too narrow in width and eventually slip as a result