Good vibrations!... or

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Rick

Rick

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Oct 5, 2004
1,098
Hunter 420 Passage San Diego
Im just curious about what is "normal" vibration with using the trusty "iron genoa" so I thought I would ask my favorite gathering of experts. My 95 336 has a 27 horse Yanny. I havent really cruised on any other hunters of late. Here is what I have: At idle she is smoothe (yes with an e). At 22-2500 rpm, she feels about like putting your hand on top of your cabin dehumidifier. At 6 plus knots... all is still well. At 28-3000 rpm, reminds me of going down the highway on that out of balance tire I have been putting off getting fixed. Doesnt chatter the teeth but... At 3300 plus or minus 100, vibration is really noticable. Will keep your boat drink sitting at the helm well mixed. Is the prop just digging? At 3600 to firewalled, she smoothes back some... kinda like holding the handle of the lawnmower (assuming your first mate doesnt already do that for you). And at 9 knots or so, the skier we are pulling doesnt even notice :D Here is the trouble shooting I have done. I checked her in neutral. You could cut a diamond on the cylinder head throughout the rpm range. I had the prop pulled and balanced. Im still running the stock 2 blader. Checked the tranny and the shaft at the stuffing box. No unusual vibration there. Had the cutlass bearing replaced 6 months ago and the bolts are tight on top. Anyone else similar or should I go ahead and get that emergency life raft? Keep my Sea Tow membership current? ObiFred.. your thoughts? cheers Rick s/v Whiskey Chaser
 
S

Steve

Similar situation

I have a similar situation. My alignment seems good, the prop isn't damaged, the cutlass bearing is OK, and the stuffing box is fine. My boat is on the hard now and when I run the engine and put her in gear, the vibration is acceptable. When I had her in the water at the end of last season, there seemed to be excessive vibration. You have an interesting thought - that it might just be the old two blade prop hacking at the water in wake of the keel. I wonder if a three blade prop would be better or maybe we have an microscopic bend in our shafts or a miniscule misalignment (doesn't seem like either of these would make a huge difference). Anybody else with a thought on this?
 
W

William

Vibration control

Try replacing the rubber washers on the engine mounts beneathe the engine. Vibrations and sounds are transmitted through these bolts. I have a 3GM30 Yanmar on a 1988 Cal 33., and have replaced the thick rubber washers with even thicker, softer new rubber which has reduced sound and vibrations by about half.
 
V

Vic "Seven"

Like a tire on a car ... there always seems ...

to be a rough spot where the table rattles or something else is making noise... I just try to avoid using that speed. Works for me ... same boat Yanmar 2GM 20 years. Looks like you still have a lot of power where you need it, and who said to go over 3000 anyway? Vic
 
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Pat McCartin

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Jun 3, 2004
347
Hunter 30_74-83 Lake Lanier, GA
Rick...

There is definatly a problem. From your description there is an issue in the drive line. The shaft might be slightly bent. Have you checked the alignment? It should be .001" per inch of diameter of the coupler. I can't lay blame on the prop if it's been balanced. I have many boats here with 2 blade props and none of them fit your description. A question. When you run in gear do you get vibration/shaking of the shaft at the packing gland? Another thought came to me...How old is your trans fluid? is it ATF or engine oil? if it's engine oil is it multi-grade or a straight weight? Pat McCartin Inland Marine Diesel Buford, Ga imd_ga@hotmail.com
 
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Pat McCartin

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Jun 3, 2004
347
Hunter 30_74-83 Lake Lanier, GA
One other thing...

Your geting 9 kts at 3600RPM? is the by the boat's knotmeter or GPS? What RPM is firewalled for you? Pat
 
Rick

Rick

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Oct 5, 2004
1,098
Hunter 420 Passage San Diego
Pat, lot to think about

Um.. Pat Lets pretend for just a second that I dont know anything about metalurgy or "diameter of the coupler" (and I thought flight school was tough). How do I measure that (read hire someone)? Your kinda bummin me out with the bent shaft thing. Will check for vbbration at the packing gland next week. What else.. oh yeah, the fluid is Yanmar engine and im not sure if its straight or multi.. will have to check. Think that could matter? Finally, paddle wheel said 8.3, GPS 8.6 with the assumption the tack is accurate although folks here say the run a bit low. "Military" power is about 3800 and I just cant push her any harder than that. 'Fraid she will spit the impeller at me. Isnt there a time where I just get to sail it? Good thing I love to tinker. Cheers Rick
 
Rick

Rick

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Oct 5, 2004
1,098
Hunter 420 Passage San Diego
What about reverse

Hey Pat One other thing. I didnt check any of the above symtoms in reverse. Wouldnt that isolate the prop if the vibrations are reduced? Or is that thinking to far outside the box :) Right back at ya Rick
 
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Big Windy

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Jun 2, 2004
1,077
Several Catalinas C25/C320 USA
Ask An Expert

These forums are good, but sometime we need to ask an expert...try: http://forums.torresen.com/sailing/ or the Yanmar site: http://www.yanmarhelp.com/msgboard.mv
 
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Pat McCartin

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Jun 3, 2004
347
Hunter 30_74-83 Lake Lanier, GA
Follow up...

Measuring the alignment isn't that hard. Get a set of feeler guages, loosen the coupler bolt. DO NOT remove them, just unlock them to finger tight. Now measure the gap between the coupler halves with the feeler guages. There should be no more than .004" difference anywhere around the coupler. Iusualy measure at 12, 3, 6, and 9. Now the RPM issue. I'd get someone in there with a photo tach to verify youe engine speed. NO load max on a GM series is 3750=/- 50 rpm. Max continous should be 3400, with WOT under load around 3600 rpm. It sounds like your govenour is set wrong and you might be over driving the prop. Are you getting any smoke at WOT? Checking in reverse would isolate the foreward drive gear only. Pat McCartin Inland Marine Diesel Buford, Ga imd_ga@hotmail.com
 
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Pat McCartin

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Jun 3, 2004
347
Hunter 30_74-83 Lake Lanier, GA
At ease

Thanks for your support Pat McCartin Inland Marine Diesel Buford, Ga imd_ga@hotmail.com Member A.B.Y.C. A.B.Y.C. certified diesel tech.
 
Rick

Rick

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Oct 5, 2004
1,098
Hunter 420 Passage San Diego
Now we are getting some where

Lets see where to start. I think I could take the measurements but because im only a "fly by night" mechanic im gonna get some help to make sure I do it right. I also did some other research so I could be just a bit smarter when talking to ya. I havent checked the mounts although I assume they are original (im second owner). I understand the misallignment or if they have gotten soft can account for vibration. As far as checking the "govna", I really dont plan to run her at high RPM unless under emergency like Yanmar says I can. I just "clear the carbon" once a month. She doesnt blow any unusual smoke at any RPM. I do know what a cavitating prop feels like if that is what you are referring too when you say overdriving. One last thing.. thanks for taking the wind out of my sails on the reverse thing. Thought I had a good idea there for a sec :( One thing at a time and thanks so much for your insight. Pat thanks for the credential verification.. like I didnt believe ya. Oh and at ease.. thanks for the links. I checked them out too. Saw alot of familiar names there :) Cheers Rick
 
D

dwain

Rick

are you going to be at the boat 2/17-2/20? We're going over that weekend, maybe we could do the dinner thing or perhaps (dah!) go sailing. dwain
 
Rick

Rick

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Oct 5, 2004
1,098
Hunter 420 Passage San Diego
Yep.. sorta

Hey Dwain, Good to hear from ya again. Yep, I will be there but on biz so not landing until 1320 on sunday. Will be there that afternoon though. How bout you? Rick
 
D

Dwain

Maybe

another time. I'm driving over Weds pm, lots of stuff to haul. The wife is flying over Fri pm, so I'll have two days of boat chores. We'll probably be leaving about the time your arriving. Good luck with the vibration. I'm going to pay close attention to mine('98 H340, 3GM30, 2 blade prop). It seems like it has always been a bit rough. It doesn't rattle your teeth, but it does make for a loud experience in the head. I haven't hauled the boat yet, I'm thinking it will be the end of the month and I'm going to have the cutlass bearing check/changed with the bottom. Dwain
 
Rick

Rick

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Oct 5, 2004
1,098
Hunter 420 Passage San Diego
But wait there is more

Hey Dwain Talked with the first mate. Im not working those days so we thought we might join you Wed afternoon and then go to phx fri morning. What do ya think. We should probably trade cell numbers. Dont know where you got the first mate tickets but, SWA has a refundable one way fare on friday for 93 bucks. Oh and that pays my salary :) Will be in touch. Cheers Rick
 
Fred Ficarra

Fred Ficarra

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Dec 2, 2003
4,245
- - Seabeck WA
Rick, I just tuned in,

Looks like you're well taken care of. I'm hanging here to see what happens. :)
 
Rick

Rick

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Oct 5, 2004
1,098
Hunter 420 Passage San Diego
TY Fred

Yep pretty happy with Patrick's input. I just dont want anything sneaking up on me. And the good news is I will get to do a comparison to Dwain's 34 which is right next door. So much to learn... Cheers Rick
 
Rick

Rick

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Oct 5, 2004
1,098
Hunter 420 Passage San Diego
Didnt get time

Hey Patrick Thanks for following up. Got hung up going over there and didnt get any time (one evening). Plan to go over tomorrow, although the forecast is gloomy for San Diego so... I have your email so I will get back to you with my findings as soon as I have found them. Cheers Rick
 
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