Ok, first stupid question about my new to me 1994 35.5 Legend. After an approx. 16 hour motorsail, moving it from Pensacola Bay to Panama City, the drive belt for alternator and water pump seem shot (3GM30) and at the end of its adjustment. Would an automotive parts house have a belt that will work or do I need to order Yanmar item. Any tips on getting tension right and do I work it from back side of the alternator where the bolt head that attaches to the adjusting arm is? Can't seem to figure out what I can put a pry bar or long screwdriver on to get tension. Thanks in advance.
Yanmar parts?
- Thread starter Marc Honey
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Best to get a Yanmar part, but if you can read the maker's number off the back of the belt go to the auto shop with this info AND the old belt. In desperation measure round the back of the belt with a steel flexible tape measure, deduct an estimate for 'stretch and wear' then use an auto item. They are the same spec really.
Best to get a Yanmar part, but if you can read the maker's number off the back of the belt go to the auto shop with this info AND the old belt. In desperation measure round the back of the belt with a steel flexible tape measure, deduct an estimate for 'stretch and wear' then use an auto item. They are the same spec really.
Spare Parts Kit
http://www.marinedieseldirect.com/yanmar/shopping/multi.php?spnum=3GM30MK&name=3GM30%20Minor%20Spare%20Parts%20Kit&image=ys.jpg&multi=1 Just for peaco of mind why not pick up a spare parts kit for your specific engine? There seems to be several different variations of your engine but the site above carries kits with or without a waterproof box as follows.. 1 104211-42070 IMPELLER, COOLING WATER 1 104211-42090 GASKET 1 104211-42100 SEAL TC10 25 7, OIL 1 104211-42110 RING, WATER SEAL 1 104500-55710 FUEL FILTER / ELEMENT FOR MOST GM AND HM SERIES ENGINES AS WELL AS SOME QM ENGINES SEE DESCRIPTION FOR DETAILS 1 104511-78780 V-BELT 1 119660-35150 LUBE OIL FILTER FOR MANY GM SERIES ENGINES 3 123210-09310 PACKING 1 124060-59380 PLUG 1 128270-12540 AIR FILTER / ELEMENT / SILENCER 2GM, 3GM(D), 2GMF, 3GMF, 2GM20, 3GM30, 2GM20F, 3GM30F 1 128670-77350 V-BELT (A-31) 2GM20, 3GM30, 3HM 1 23418-060000 BLEEDER PLUG PACKING 1 24341-000440 O-RING 1A S-44.0 3 27210-200300 ANTI-CORROSIVE ZINC
http://www.marinedieseldirect.com/yanmar/shopping/multi.php?spnum=3GM30MK&name=3GM30%20Minor%20Spare%20Parts%20Kit&image=ys.jpg&multi=1 Just for peaco of mind why not pick up a spare parts kit for your specific engine? There seems to be several different variations of your engine but the site above carries kits with or without a waterproof box as follows.. 1 104211-42070 IMPELLER, COOLING WATER 1 104211-42090 GASKET 1 104211-42100 SEAL TC10 25 7, OIL 1 104211-42110 RING, WATER SEAL 1 104500-55710 FUEL FILTER / ELEMENT FOR MOST GM AND HM SERIES ENGINES AS WELL AS SOME QM ENGINES SEE DESCRIPTION FOR DETAILS 1 104511-78780 V-BELT 1 119660-35150 LUBE OIL FILTER FOR MANY GM SERIES ENGINES 3 123210-09310 PACKING 1 124060-59380 PLUG 1 128270-12540 AIR FILTER / ELEMENT / SILENCER 2GM, 3GM(D), 2GMF, 3GMF, 2GM20, 3GM30, 2GM20F, 3GM30F 1 128670-77350 V-BELT (A-31) 2GM20, 3GM30, 3HM 1 23418-060000 BLEEDER PLUG PACKING 1 24341-000440 O-RING 1A S-44.0 3 27210-200300 ANTI-CORROSIVE ZINC
Belt Tension
Your belt tension can be set by tightening the altenator to a point that allows the belt about 1/2" slack when you press on the belt in the center of the longest segment between the pulleys. To tension it, loosen both the pivot bolt/nut and the locking bolt/nut. If you don't have a belt tensioner, use a Stilson wrench (the one that looks like a dinosaur head), adjust it wide enough to hook the upper "jaw" over the end of the adjustment bar. Then hook the lower "jaw" over the locking bolt/nut. The squeeze the wrench together to move the alternator and tension the belt. When tight enough tighten the locking nut/bolt (from the back) and then the pivot nut/bolt. Job done! Good Luck!
Your belt tension can be set by tightening the altenator to a point that allows the belt about 1/2" slack when you press on the belt in the center of the longest segment between the pulleys. To tension it, loosen both the pivot bolt/nut and the locking bolt/nut. If you don't have a belt tensioner, use a Stilson wrench (the one that looks like a dinosaur head), adjust it wide enough to hook the upper "jaw" over the end of the adjustment bar. Then hook the lower "jaw" over the locking bolt/nut. The squeeze the wrench together to move the alternator and tension the belt. When tight enough tighten the locking nut/bolt (from the back) and then the pivot nut/bolt. Job done! Good Luck!
Related matter
Went to Yanmar's Deisel School in NC, where among other things they sold me on nine reasons to always use Yanmar oil filters. Beyond that, auto stores can match a lot of items.
Went to Yanmar's Deisel School in NC, where among other things they sold me on nine reasons to always use Yanmar oil filters. Beyond that, auto stores can match a lot of items.
I had a similar problem
I found that the pivot bolt on the aftermarket Balmar alternator was undersized and eventually came loose. I suspect that the smaller diameter bolt was used to make the initial installation easier when the alternator was put in. The mounting holes were elongated by the vibration of the engine. The elongated holes allowed belt misalignment which caused the belts to wear very quickly. I eventually had to ream out the hole and put in a pivot bolt sized to that diameter. That seemed to fix the excessive belt wear problem. The other problem awaiting my attention is that the alternator has a single pulley and that is not adequate to the size of the alternator (130 Amps). Add to that the fact that the water pump is run off of the same belt and when the alternator belt fails, so does the cooling and so does the engine. I plan to redesign the system so that the alternator has a double pulley and the water pump is driven by its own belt. Do you have a stock alternator? Is the belt alignment good? Were the batteries seriously discharged? My belt problem showed up only when the batteries were down and the alternator was working unusually hard to recharge them. I find that the automotive belts work just fine and are far more available and less costly. Everybody I asked had a different idea about my problem. Find a good mechanic if you aren't sure about all of this. I do not know nine reasons for buying Yanmar filters either but I haven't been to their school.
I found that the pivot bolt on the aftermarket Balmar alternator was undersized and eventually came loose. I suspect that the smaller diameter bolt was used to make the initial installation easier when the alternator was put in. The mounting holes were elongated by the vibration of the engine. The elongated holes allowed belt misalignment which caused the belts to wear very quickly. I eventually had to ream out the hole and put in a pivot bolt sized to that diameter. That seemed to fix the excessive belt wear problem. The other problem awaiting my attention is that the alternator has a single pulley and that is not adequate to the size of the alternator (130 Amps). Add to that the fact that the water pump is run off of the same belt and when the alternator belt fails, so does the cooling and so does the engine. I plan to redesign the system so that the alternator has a double pulley and the water pump is driven by its own belt. Do you have a stock alternator? Is the belt alignment good? Were the batteries seriously discharged? My belt problem showed up only when the batteries were down and the alternator was working unusually hard to recharge them. I find that the automotive belts work just fine and are far more available and less costly. Everybody I asked had a different idea about my problem. Find a good mechanic if you aren't sure about all of this. I do not know nine reasons for buying Yanmar filters either but I haven't been to their school.
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