I'm in the final pre-purchase stages on a 1992 H37.5. We conducted the mechanical inspection of the engine and the survey yesterday. I'm concerned about the engine noise and vibration which the diesel guy says is normal but perhaps a design flaw on this Yanmar 35 hp (sorry don't have the model number with me). Any other 37.5 owners experiencing this? Any solutions for it? Thanks. Gary Wyngarden
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Three Cylinder, Gary?
I had a 3gm on my 32 Vision and now have a 4jh on my 40.5. I assume your diesel guy is a competent mechanic. That being the case, and assuming proper engine alignment and good motor mounts, the vibration and noise may be normal. I did note the 3 cyl Yanmar had more vibration than the 4 cyl as you would expect. However, neither is nearly as rough as the one cylinder I had on my O'Day 27! However, you do get used to it. I've never had anything so smooth and quiet as the Atomic 4 on an old Columbia. But, I digress. What may help is to get foam insulating tape and put it on all the engine panel openings to seal them and to the edges to stop vibration. I also found a couple of floor panels would vibrate and gave them the same treatment. Sometimes the sound is panel resonance rather than actual engine noise. Good luck; great boat. Rick D.
I had a 3gm on my 32 Vision and now have a 4jh on my 40.5. I assume your diesel guy is a competent mechanic. That being the case, and assuming proper engine alignment and good motor mounts, the vibration and noise may be normal. I did note the 3 cyl Yanmar had more vibration than the 4 cyl as you would expect. However, neither is nearly as rough as the one cylinder I had on my O'Day 27! However, you do get used to it. I've never had anything so smooth and quiet as the Atomic 4 on an old Columbia. But, I digress. What may help is to get foam insulating tape and put it on all the engine panel openings to seal them and to the edges to stop vibration. I also found a couple of floor panels would vibrate and gave them the same treatment. Sometimes the sound is panel resonance rather than actual engine noise. Good luck; great boat. Rick D.
doesnt' sound right to me
Can't say that I have any noticeable vibration or noise on mine - '93 37.5. Engine has about 2k hours on it and I wouldn't say either is noticeable. Are you speaking at idle, higher at specific RPM ranges, or something else? There is a range (I think around 1800rpm) where it's there is some vibration/noise which I think is common to almost all yanmars. I have the standard 2 blade prop. What's yours and could that make a difference? My former boat was H31 with the 2cyl Yanmar It did vibrate, expecially in reverse, but I think that was due to worn engine mounts. I haven't used a 4 cyl so I can't compare to them. Based on what you're reporting, I'd consider getting a second opinion.
Can't say that I have any noticeable vibration or noise on mine - '93 37.5. Engine has about 2k hours on it and I wouldn't say either is noticeable. Are you speaking at idle, higher at specific RPM ranges, or something else? There is a range (I think around 1800rpm) where it's there is some vibration/noise which I think is common to almost all yanmars. I have the standard 2 blade prop. What's yours and could that make a difference? My former boat was H31 with the 2cyl Yanmar It did vibrate, expecially in reverse, but I think that was due to worn engine mounts. I haven't used a 4 cyl so I can't compare to them. Based on what you're reporting, I'd consider getting a second opinion.
Rick, you reminded me of my smooth Atomic 4
It was even smoother after the crankshaft broke in half, 200 miles from home in Desolation Sound.
Too bad we couldn't use it.
It was even smoother after the crankshaft broke in half, 200 miles from home in Desolation Sound.
Too bad we couldn't use it.Engine Vibration
I bought my 37.5 two years ago. This is the first crusing boat I have owned. I had read somewhere on this web site that vibration is one of the characteristics of this motor. Being the worrier that I am, I listened to and looked at the motor and thought there was too much vibration. The mechanic who did the pre-purchase inspection thought the motor was fine. All through the first year, I thought there was too much vibration and the mechnaic did not know what he was talking about. Last September (after my second year with the boat), another mechanic looked at the motor and said everything was great. Even the motor mounts, that have been an issue with some yanmars, were fine. Other than changing oil, belts and filters we have put no money in the motor. The second mechanic was there to give us a hands on lesson on how to bleed the fuel system, change the water pump impellor, etc. We have about 1000 hours on the engine. I suppose I will always worry about my motor, but I am not a mechanic and really have nothing to which to compare the vibration level. Unless you can put a couple of these boats side by side and look at the engines in operation, I believe it would not be easy to judge vibration levels.
I bought my 37.5 two years ago. This is the first crusing boat I have owned. I had read somewhere on this web site that vibration is one of the characteristics of this motor. Being the worrier that I am, I listened to and looked at the motor and thought there was too much vibration. The mechanic who did the pre-purchase inspection thought the motor was fine. All through the first year, I thought there was too much vibration and the mechnaic did not know what he was talking about. Last September (after my second year with the boat), another mechanic looked at the motor and said everything was great. Even the motor mounts, that have been an issue with some yanmars, were fine. Other than changing oil, belts and filters we have put no money in the motor. The second mechanic was there to give us a hands on lesson on how to bleed the fuel system, change the water pump impellor, etc. We have about 1000 hours on the engine. I suppose I will always worry about my motor, but I am not a mechanic and really have nothing to which to compare the vibration level. Unless you can put a couple of these boats side by side and look at the engines in operation, I believe it would not be easy to judge vibration levels.
Smooth running
Are you sure the vibration is in the motor? We have a 3HM (35 HP)in our Legend and it runs as smooth as the atomic 4 in our old Ericson at any given RPM over idle and in neutral, also it is very smooth underway.(except) It jerks when it starts then smooths out nicely and there is a vibration when underway that I have traced to the shaft log and prop shaft coupling.(not the motor) The vibration starts around 1,850 rpm and quits at above 2,000. The prop shaft is straight but is too close to the shaft log and drags on it making the vibration. I think if the motor and shaft alignment was changed so the shaft was centerd properly in the log and indicated into correct alignment with the motor it would be smooth at all rpm's.
Are you sure the vibration is in the motor? We have a 3HM (35 HP)in our Legend and it runs as smooth as the atomic 4 in our old Ericson at any given RPM over idle and in neutral, also it is very smooth underway.(except) It jerks when it starts then smooths out nicely and there is a vibration when underway that I have traced to the shaft log and prop shaft coupling.(not the motor) The vibration starts around 1,850 rpm and quits at above 2,000. The prop shaft is straight but is too close to the shaft log and drags on it making the vibration. I think if the motor and shaft alignment was changed so the shaft was centerd properly in the log and indicated into correct alignment with the motor it would be smooth at all rpm's.
Smooth running
Are you sure the vibration is in the motor? We have a 3HM (35 HP)in our Legend and it runs as smooth as the atomic 4 in our old Ericson at any given RPM over idle and in neutral, also it is very smooth underway.(except) It jerks when it starts then smooths out nicely and there is a vibration when underway that I have traced to the shaft log and prop shaft coupling.(not the motor) The vibration starts around 1,850 rpm and quits at above 2,000. The prop shaft is straight but is too close to the shaft log and drags on it making the vibration. I think if the motor and shaft alignment was changed so the shaft was centerd properly in the log and indicated into correct alignment with the motor it would be smooth at all rpm's.
Are you sure the vibration is in the motor? We have a 3HM (35 HP)in our Legend and it runs as smooth as the atomic 4 in our old Ericson at any given RPM over idle and in neutral, also it is very smooth underway.(except) It jerks when it starts then smooths out nicely and there is a vibration when underway that I have traced to the shaft log and prop shaft coupling.(not the motor) The vibration starts around 1,850 rpm and quits at above 2,000. The prop shaft is straight but is too close to the shaft log and drags on it making the vibration. I think if the motor and shaft alignment was changed so the shaft was centerd properly in the log and indicated into correct alignment with the motor it would be smooth at all rpm's.
Noisy but no Vibration
On my '94 375, the 38hp 3jh2e engine is loud, but there's no more vibration than I've felt on other boats that size. There does seem to be harmonic vibration at specific rpms, but that's not unusual. As was suggested, some additional soundproofing of the engine compartment might be helpful. Gary, since you're apparently crawling around in the innards of this new boat, would you please read my post in the big boats forum "Q for 375 owners", take that measurement on your boat and post the measurement for me? Thanks.
On my '94 375, the 38hp 3jh2e engine is loud, but there's no more vibration than I've felt on other boats that size. There does seem to be harmonic vibration at specific rpms, but that's not unusual. As was suggested, some additional soundproofing of the engine compartment might be helpful. Gary, since you're apparently crawling around in the innards of this new boat, would you please read my post in the big boats forum "Q for 375 owners", take that measurement on your boat and post the measurement for me? Thanks.
Noise etc.
Gary, One question to ask is what kind of noise is it. I can think of a couple of things you might want to look at. 1) Exhaust noise, i.e. the engine seems loud when sitting at the wheel: check the exhaust/raw water mixing elbow and make sure you're not all carboned up. If the engine is run at low loads for a long time, such as battery charging at anchor, this can be a problem. 2) Tapping noises noticed while below: check the valve clearances. This is pretty easily identified by a screwdriver against the valve cover when the engine is running (watch out for the belt!). Tapping can also be from the fuel pump so that's something to think about. 3) Knocking - if at idle you might be idling too low I like mine at about 800 RPM. If at all speeds and particularly when in gear check the motor mounts. There are two possible metal-metal contact points and a casual inspection will look OK but they're still shot. 4) Thumping - in gear. My guess would be a mis-alignment of the shaft. Check this by looking at the shaft coupling flange with the engine running, the boat in gear at a fast idle. If the flange is wobbling back and forth or up and down it needs realignment. Your motor has a personality and will have it's own transient vibration range and the odd noise from time to time. Once you get a few more hours on it you'll get a better idea of what's "normal" and what's not. Good luck with your new boat. Jim h37.5 "Esmeral" currently in Beaufort, NC
Gary, One question to ask is what kind of noise is it. I can think of a couple of things you might want to look at. 1) Exhaust noise, i.e. the engine seems loud when sitting at the wheel: check the exhaust/raw water mixing elbow and make sure you're not all carboned up. If the engine is run at low loads for a long time, such as battery charging at anchor, this can be a problem. 2) Tapping noises noticed while below: check the valve clearances. This is pretty easily identified by a screwdriver against the valve cover when the engine is running (watch out for the belt!). Tapping can also be from the fuel pump so that's something to think about. 3) Knocking - if at idle you might be idling too low I like mine at about 800 RPM. If at all speeds and particularly when in gear check the motor mounts. There are two possible metal-metal contact points and a casual inspection will look OK but they're still shot. 4) Thumping - in gear. My guess would be a mis-alignment of the shaft. Check this by looking at the shaft coupling flange with the engine running, the boat in gear at a fast idle. If the flange is wobbling back and forth or up and down it needs realignment. Your motor has a personality and will have it's own transient vibration range and the odd noise from time to time. Once you get a few more hours on it you'll get a better idea of what's "normal" and what's not. Good luck with your new boat. Jim h37.5 "Esmeral" currently in Beaufort, NC
Probably Need Not Worry
Gary, Any used boat will need some preventative maintenance after a purchase, if for no other reason than peace of mind. I perform certain types of preventative maintenance on my 1992 37.5 whether there is trouble or not. Comes from my aviation days, I suppose. ;-) 1. It would not hurt at all to have the valves readjusted and the injectors cleaned at some point in the near future and then every couple of seasons after that. These two relatively small jobs are important to good fuel economy and will affect the engine's ability to start properly and run efficiently. 2. Engine alignment, although probably not an issue normally, should be checked and adjusted accordingly every season. 3. I have had trouble with the exhaust elbow in the past. For the money and the potential damage that a bad exhaust elbow can do to an engine, change this part every five years. If you are not sure about the one in the boat at the moment, change it. 4. Every third season on all my boats, I have the fuel tank professionally drained and cleaned. Then, use clean fuel, no additives, change the filters regularly (Every 100 hours or so), and you should be on your way with little trouble at all.
Gary, Any used boat will need some preventative maintenance after a purchase, if for no other reason than peace of mind. I perform certain types of preventative maintenance on my 1992 37.5 whether there is trouble or not. Comes from my aviation days, I suppose. ;-) 1. It would not hurt at all to have the valves readjusted and the injectors cleaned at some point in the near future and then every couple of seasons after that. These two relatively small jobs are important to good fuel economy and will affect the engine's ability to start properly and run efficiently. 2. Engine alignment, although probably not an issue normally, should be checked and adjusted accordingly every season. 3. I have had trouble with the exhaust elbow in the past. For the money and the potential damage that a bad exhaust elbow can do to an engine, change this part every five years. If you are not sure about the one in the boat at the moment, change it. 4. Every third season on all my boats, I have the fuel tank professionally drained and cleaned. Then, use clean fuel, no additives, change the filters regularly (Every 100 hours or so), and you should be on your way with little trouble at all.
Steve, you're more obsessive than I am.
All good advice. But changing your fuel filters at 100 hours is really obsessive. I get more than that much time on a fill up.
All good advice. But changing your fuel filters at 100 hours is really obsessive. I get more than that much time on a fill up.
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