2005 R21 and Yanmar 3YM30 motor mounts

[R21]

My motor mounts still look good but the manual calls for new motor mounts every four years or 1,000 hours, whichever is less. Can someone comment on their own experience with 3YM30 motor mounts? How often do you replace? It looks like about $600 in parts plus freight, today. Thank-you in advance.
Denis

 

[GA-Midnight Cruise]

Denis, replace them if and when they fail. I have three R21's. One is a 2005 with a 3YM30 and the original mounts are as good as the day they were installed. Enjoy that tug.

 

[R21]

Many thanks for this, GA-Midnight Cruise.
Denis

 

[Newf]

Hi R21, Here's a link with a bit of discussion on engine mounts.

Not a mechanic myself but I would not agree with waiting for mounts to "fail" before replacing them. With that being said I have no recommendation on when they should be replaced. Rubber mounts fatigue over time and usage, so unless measurements are recorded for day one and monitored over time it would be difficult to say how much they have "sagged". Hardness of the rubber also changes over time which can affect how the engine reacts. I believe it is for this reason the engine manufactures recommend they be replaced at a given interval. Will the engine still run with worn mounts?? Yes. Will it be optimum? Depends on how badly they are worn. Will engine vibration change or increase with age of mounts? Yes IMO.

I have the Volvo-Penta so my mounts are a different design than yours but just had to replaced mine as the rubber was starting to crack and "sag". Over $900.00 Can. so not a cheap exercise.

I would think that a good check to determine if your mounts have changed much in height would be to check coupling alignment. When i checked mine with the old mounts still in place, there was a .040" difference between top and bottom. I think side to side was only .005" difference. Recommended difference for my coupling is .003" or less. Going forward I will check the alignment at every 300-400hr interval, which is about every year for me.

http://www.oceannavigator.com/November- ... ne-mounts/

 

[Swansboro Dave]

If you do switch out with new mounts I may be interested in purchasing your old mounts.

 

[R21]

If you do switch out with new mounts I may be interested in purchasing your old mounts.

Received OK

 

[R21]

If you do switch out with new mounts I may be interested in purchasing your old mounts.

Received OK

Hi R21, Here's a link with a bit of discussion on engine mounts.

Not a mechanic myself but I would not agree with waiting for mounts to "fail" before replacing them. With that being said I have no recommendation on when they should be replaced. Rubber mounts fatigue over time and usage, so unless measurements are recorded for day one and monitored over time it would be difficult to say how much they have "sagged". Hardness of the rubber also changes over time which can affect how the engine reacts. I believe it is for this reason the engine manufactures recommend they be replaced at a given interval. Will the engine still run with worn mounts?? Yes. Will it be optimum? Depends on how badly they are worn. Will engine vibration change or increase with age of mounts? Yes IMO.

I have the Volvo-Penta so my mounts are a different design than yours but just had to replaced mine as the rubber was starting to crack and "sag". Over $900.00 Can. so not a cheap exercise.

I would think that a good check to determine if your mounts have changed much in height would be to check coupling alignment. When i checked mine with the old mounts still in place, there was a .040" difference between top and bottom. I think side to side was only .005" difference. Recommended difference for my coupling is .003" or less. Going forward I will check the alignment at every 300-400hr interval, which is about every year for me.

http://www.oceannavigator.com/November- ... ne-mounts/

Good thoughts. I have not done anything. I put very few hours on the engine. The rubber looks good. There is now vibration on startup but it soon goes away. Thanks for your comments, above. I will use your alignment suggestion.

Denis, replace them if and when they fail. I have three R21's. One is a 2005 with a 3YM30 and the original mounts are as good as the day they were installed. Enjoy that tug.

Thanks for this comment. Mine is 2005. I have only 320 hours on it. Rubber looks good. No rust anywhere. No run in salt water. Engine vibrates on startup but soon calms down. No undesirable vibration while running.