# Kanzaki transmission questions



## rbyham (Dec 25, 2012)

I am trying to track down a new noise emanating from my engine compartment. The engine is a 1978 Yanmar 3qm30 with a bolted on Kanzaki transmission. The ID plate for the trans is attached. 

The sound is like that of those Mexican percussion instruments that are shaken. I think they are called maracas and have the sound of dry rice inside.

The sound only happens in gear and more so in forward. I also notice that when put in gear I hear a solid "clunk" sound of engagement. A local mech told me this is a good sign on the trans as a smooth gradual engagement indicates plates going. Not sure on that one. Anyway I was wondering if folks here who have experience with this setup might have some ideas for me as far as indicators on the trans or other potential sources of the noise. Thanks...


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## FarCry (Apr 21, 2007)

Perhaps a problem with the flex plate or the attached springs? If it is failing/failed maybe under load its moving around and letting things clatter. I assume you've checked the fluid in your transmission and it looks and smells OK, not burnt.


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## RichH (Jul 10, 2000)

There is a slight possibility that the flex plate has become noisy; but, a failing flex plate will usually be heard at all engine rpms. 
. 
However, there is a stronger possibility in the Kanzaki KBW-10 that's normally coupled to a 3QM30 .... that the internal oil screen/filter has never been cleaned. The KBW-10 has an integral output shaft driven oil pump and that oil pump has an internal 'strainer/filter/screen that 'should' be cleaned each and every time the trans. fluid is changed. If this fine mesh metal 'strainer' (for to capture clutch fricion material , etc.) assembly is not cleaned, the output shaft bearings will rapidly and adversely wear (because they become 'dry' without a constant oil/fluid supply). This output shaft connected oil pump insures that the transmission is _constantly_ lubricated when the prop is spinning when the transmission is (properly) left in neutral when sailing.
The access to this 'strainer' is slightly below and off to the (right ?) side of the output shaft at the rear of the transmission - a LARGE hex head.

The symptoms of a blocked oil strainer (and severely worn tail shaft bearings ... and ultimately leading to severely leaking shaft seals) are usually a slight 'grinding noise' when the transmission is in forward and with the engine idling, this will be the 'loudest' symptom; and, will initially 'disappear' as engine rpm increases. Such is also the result of: 1. many years of _improper engine to coupler alignment_ (FWIW - Yanmar engine mounts only last about 500-1000 hours and should then be replaced), and 2. NOT cleaning out that strainer every time one changes the transmission fluid - which should be changed _EVERY time one changes the engine lube oil_.

In a worst case scenario, a KBW-10 will cost about $1500-1800 for a complete 'pro' rebuild, not including removal and re-instalation costs. 
:-(


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## rbyham (Dec 25, 2012)

Thanks folks but the trans is the KH18. I don't think it has an integral filter/screen. Not sure what to do next. Seems to run fine. Goes into forward and reverse immediately and pushes the boat well in either direction. Fluid needs changed so will do that and see. I do wonder about mounts. Found front starboard side nuts completely off a couple weeks ago and reset. Shaft turns very smooth to the eye and seems centered well on shaft log. So I feel good about alignment. So I'll change fluid and go from there. Some have suggested possibility of bad cutlass which is quite likely. But I was hoping to get to Fall before haul. Too hot to do bottom and cutlass in Charleston these days.


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## Capt Len (Oct 9, 2011)

Rich obviously knows his stuff. My experience with drive plates is much more negative. Some work boats change them as part of seasonal maintenance. Seen them pop the bolts than hold them on the flywheel and throw springs into the bell housing cavity to rattle around. Easy to eliminate by switching to the rubber cog type which I prefer. Not surprised if lack of maintenance catches up with some folks. The shaft needs to be unbolted from the flange before you can determine alignment


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## RichH (Jul 10, 2000)

A correction - 
Sorry, my memory had failed when tapping onto my cellphone and I erred in that the typical config. of the 3QM30 usually has the KH-18 ... and all the itemization that I previously listed applies to the KH-18 (and NOT the KBW-10). Apologies.

The KH-18, usually mounted to the 3QM30, is the one with the internal shaft driven oil pump ... and is the one with the filter/strainer screen (dwg.PN 27-18) that easily blocks the pump when fouled with debris.

So, what to do next is to remove the large plug near (to the starboard aft side and 'above' from the tailshaft/coupler, and examine if indeed that internal screen/strainer is covered/blocked with debris. If so, then suspect that the bearings are beginning to 'go'. As stated before if the screen is blocked, and there _is_ bearing noise, the next thing to go will probably be the rear oil seal. 
Suggest: 
1. inspect/clean the oil screen. 
2. check engine/coupler alignment --- (many times a precise engine alignment will 'help' to quiet down transmission bearing noise on the 3QM30 ... for a while). Use feeler gages when checking engine to coupler alignment; attempt to get the alignment 'perfect' - 0.001±" face to face.

;-)


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## rbyham (Dec 25, 2012)

RichH said:


> There is a slight possibility that the flex plate has become noisy; but, a failing flex plate will usually be heard at all engine rpms.
> .
> However, there is a stronger possibility in the Kanzaki KBW-10 that's normally coupled to a 3QM30 .... that the internal oil screen/filter has never been cleaned. The KBW-10 has an integral output shaft driven oil pump and that oil pump has an internal 'strainer/filter/screen that 'should' be cleaned each and every time the trans. fluid is changed. If this fine mesh metal 'strainer' (for to capture clutch fricion material , etc.) assembly is not cleaned, the output shaft bearings will rapidly and adversely wear (because they become 'dry' without a constant oil/fluid supply). This output shaft connected oil pump insures that the transmission is _constantly_ lubricated when the prop is spinning when the transmission is (properly) left in neutral when sailing.
> The access to this 'strainer' is slightly below and off to the (right ?) side of the output shaft at the rear of the transmission - a LARGE hex head.
> ...


Rich... rereading your very helpful post I do want to make sure I get to that strainer. Looking at the 3qm30 manual it is unclear which bolt is the strainer. But I found a pic on the net of the back of my trans and have marked what I think is the bolt with an arrow. Can you confirm this is it? If so and I get that bolt out is there anything I need to be aware of in the way of springs or such in there? Any suggestions on best way to clean mesh once out? Thanks much for your help...


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## Jeff_H (Feb 26, 2000)

Rich's points, and particularly about alignment, are worth heeding. To add to the discussion, I think that I have the a similar engine (3GM 30) but the same transmission. I just pulled my engine out last month and removed the transmission to replace the main crankshaft seal on the engine. 

A couple thoughts here, first of all, my boat has always had a certain amount of gear whine when in gear, but not very loudly. But fi yours is pretty loud, then my next suspicion would be with the damper plate. There is a tendency to put the damper plate in backwards. If you don't know better, and if you hold the damper plate in your hands and look at where it is installed, or look at the engine manual, it is easy to think it goes in facing the wrong way. I am told by a reputable mechanic that if it is installed facing backwards, it will make noise and it will damage the transmission over time. As an amateur mechanic, I had forgotten to mark which side of the plate faced out, and so I almost installed it facing the wrong way. 

If your boat has always made that noise, it would make sense to try to find out if the transmission has ever been removed from the engine. If the transmission has been removed, as much as I hate to say this, you may need to have a mechanic remove the transmission and check the damper plate orientation. 

Second, it is very critical to use the right oil (single weight SAE 30) and fill the transmission oil to the correct height; no higher and no lower than the marks. Absent that, the transmission will not engage properly and may make noise. 

Check the shift linkage and make certain that it fully engages the transmission into gear in both directions. That should be checked periodically since the adjuster on the cable system is a pretty crude clamp and can slip over time. Failure to properly fully engage the transmission will cause wear and noise. 

Mine also has a distinctive clunk when it goes into gear which I am told is normal and a sign of a healthy transmission. 

Jeff


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## RichH (Jul 10, 2000)

rbyham said:


> Rich... rereading your very helpful post I do want to make sure I get to that strainer. Looking at the 3qm30 manual it is unclear which bolt is the strainer. But I found a pic on the net of the back of my trans and have marked what I think is the bolt with an arrow. Can you confirm this is it? If so and I get that bolt out is there anything I need to be aware of in the way of springs or such in there? Any suggestions on best way to clean mesh once out? Thanks much for your help...


Yes, That's the hex head that constrains the 'strainer'. Mechanical scrubbing will clean it - a toothbrush and some 'solvent'.
This transmission uses Dexron ATF fluid .... it should be so listed on the ID plate on the top gear cover plate mounted next to the fill port/dip stick. Some use a spring to hold in the 'strainer', some use soft rubber bushings as an interference fit (tight fit) - that Ive seen.

JeffH makes a very valid point about checking the engagement of the shifting cable, as morse type cables do rust and bind. Disconnect the control cable from the the 'shifting arm'. Be sure the arm is in neutral, reinsert the cable - you may have to readjust either the pinch clamp that holds the outer cable to the engine body, or the clevis that attaches to the shifting arm ..... so that the pin in the clevis can be inserted without moving the shifting arm. Any 'preload' to the shifting arm by mal-adjustment can apply pressure and slight 'engagement' to the friction discs. Check the cable to shafting arm engagement for all three - fwd/neutral/rev. in their 'resting' positions re: the shifting arm.

The primary cause of transmission bearing wear is engine mis-alignment as it causes side forces on the tail/output shaft and which can tend to 'slightly bend' the tail shaft during rotation - that's why engine alignment is VERY important. The engine mounts are soft rubber devices, and that rubber will slowly change dimensions over time with the weight of the engine/transmission on them - the engine/transmission will very slowly 'sink' into the soft rubber of the engine mounts. Yanmar engine mounts for the 3QM30 are very expensive ... but you really have to keep adjusting the mounts and probably replace them at least a minimum of every every 1000 engine hours. However, the cost of new mounts is less expensive than a transmission 'rebuild'.

A good practice when aligning the engine is to measure (in thousandths of inches) the 'total height' of the flat top surfaces of the engine mounts TO the top of the engine bed, etc. --- will give a coarse indication of how much the mounts have changed dimension when you do the 'next' precision engine alignment - for less 'guess work'.


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## casey1999 (Oct 18, 2010)

RichH said:


> A correction -
> Sorry, my memory had failed when tapping onto my cellphone and I erred in that the typical config. of the 3QM30 usually has the KH-18 ... and all the itemization that I previously listed applies to the KH-18 (and NOT the KBW-10). Apologies.
> 
> The KH-18, usually mounted to the 3QM30, is the one with the internal shaft driven oil pump ... and is the one with the filter/strainer screen (dwg.PN 27-18) that easily blocks the pump when fouled with debris.
> ...


Would the Kanzaki KM3V transmission have this same oil screen filter? That is the transmission I have and have never seen a maintenance requirement for this transmission other than changing the 30 wt oil.


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## RichH (Jul 10, 2000)

It is my understanding that only the KH-18 has the oil pump, most other Kanzaki's from this era are 'splash lubricated'


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## rbyham (Dec 25, 2012)

Thanks all for the help... Rich especially... I will be back on Friday from a business trip and hope on the weekend to change fluidfluid, clean mesh and check the other alignment and shift lever issues. Thanks again...


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## RichH (Jul 10, 2000)

Forgot to mention ... the KH-18's case is easily cracked as a long term result of engine misalignment. When you assay, look carefully about the external surfaces for thin cracks in the housing casting. Once cracks develop, the gear train will no longer be in perfect alignment/gear 'lash' etc. and you will then probably have NOISE due to 'run out' of the gearing .... . 
Good luck.


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## casey1999 (Oct 18, 2010)

rbwham,
Just a few items you may want to also check:

1. Can you run the engine/ transmission in fwd and rev while the prop shaft is disconnected? This might tell you if the problem is with the cutlass or shaft or with the transmission.

2. I have a bad cutlass bearing I am now replacing- the bad cutlass gives a low freq rumbling sound or a thumping sound. At one point I also had a grinding sound coming from the trans/prop shaft. The cause turned out to be a slip of the prop shaft on the coupling which then led to the prop contacting the prop shaft strut- that led to a grinding sound.

3. You may have a loose shaft zinc or prop zinc causing the noise. Dive the boat if you can and see what you find.


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## rbyham (Dec 25, 2012)

casey1999 said:


> rbwham,
> Just a few items you may want to also check:
> 
> 1. Can you run the engine/ transmission in fwd and rev while the prop shaft is disconnected? This might tell you if the problem is with the cutlass or shaft or with the transmission.
> ...


Good thoughts Casey. I will add to list of things to check this coming week. I can pull the shaft from the coupling though access is difficult and painful.


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## rbyham (Dec 25, 2012)

Pulled strainer/filter today. See pics of results. Not great but not sure how bad. Changed fluid twice running hard in gear in between. Second filter checked showed nothing. Not sure where to go next... Noise remains... But she seems to run fine... Hmmmm.


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## RichH (Jul 10, 2000)

Broken off metal shavings on strainer screen = internal damage. 

Are the shavings magnetic (iron)? If so then suspect damaged bearing races; hence bearings that no longer run 'true' - as the highest potential. 
How is the rear oil seal? ... dry or beginning to 'weep'?


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## rbyham (Dec 25, 2012)

Yeah I figured... rear seal looks dry... so next step is to pull it and open it up? I have identified a local marine trans specialist so may have him come take a look and listen as well... oh well... in the meantime i had a great sail this morning...


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## RichH (Jul 10, 2000)

Yup, time to open the top plate to wiggle and jiggle (to grossly check gear lash) and to look for obvious signs of 'gear and bearing crashing'. 
Good that you pulled the strainer - most have no idea that its even there - although those metal chips isnt a good sign. 

Typical cost for a total rehab/rebuild by the 'top shops' is in the neighborhood of $2k, .... plus removal and installation costs. 

Do look for 'fine' external case cracks FIRST as such will quickly define if the trans. is rebuildable. No sense ripping and snorting and paying if the case is a 'goner'. 

Keep us informed. Good luck to ya.


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## rbyham (Dec 25, 2012)

Thanks all... my plan at present having researched the rebuild process is to drive it for a while and monitor the filter. I have easy access to filter and so can check it regularly. I have about 3 hours of motoring to date since first discovery of metal pieces on filter and she comes out clean now. She also runs great and the rocks in coffee can noise goes away about 1200 rpm which would point to the damper plate. As we get into Fall sailing season the engine gets very little work so I believe I may get quite a bit more time until January haulout at which point I can make decisions about numerous things including the trans. If she develops more serious problems before that I know where to go for rebuild help... I will come back to update this thread whatever happens. Thanks for all the input I have received here...


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## IStream (Dec 15, 2013)

Sounds like a plan.


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## FarCry (Apr 21, 2007)

Going back to post #2 on this thread, if it is indeed a failing damper plate I wouldn't be inclined to keep running it. My damper plate failed without obvious warning. The first sign was that my tach showed zero RPM as I was nearing my slip. That alone didn't really get my attention as an impending serious issue. Docked the boat, assumed the gauge, flywheel sensor or associated wiring failed and went on my way until I had more time to investigate. Ran out of time and didn't get to it before a planned trip. Day two on the trip and an awful noise came out of the engine room moments after leaving an anchorage. Eventually I determined that springs had fallen out of plate and were slinging around via the teeth on the flywheel scraping the inside of the bell-housing. Pulled the tach sensor and saw it was destroyed. Pulled the starter and noticed some fresh shiny damage to the teeth on it. Sailed back home ending our trip very prematurely... Yes it's a sailboat but at that time I didn't have enough solar to self sustain and the motor was my only charging source. I couldn't run the motor at all without risking further damage that was obviously happening. 

Good Luck!


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## rbyham (Dec 25, 2012)

Thanks FC... good food for thought... at least my tach is not the flywheel driven version... I run off alternator... but I realize the potential for damage is still significant... just hate to go down before I have to... no long trips planned until I get whole boat in better shape. Just day sails for now. WIll keep towboat US policy updated.


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## kozyboat (Sep 27, 2015)

Anyone out there have a manual for a KANZAKI KBW20??
Just in the middle of a full overhaul... need some specs on plate thickness etc....
Also... a good source for overhaul parts?

Thanks!
Tim


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## kozyboat (Sep 27, 2015)

Finally after too many hours of surfing google I have found a good source for a manual for both the engine and transmission

YANMAR ENGINE MANUAL
KANKAZI TRANMISSION MANUAL

Yanmar Marine Service Manuals PDF Download

Well worth the few bucks, to download a full complete manual...
Very impressed with the detail for inspections and overhaul procedures.

Tim


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## mabitter (Jun 9, 2018)

Hi all - 

Whatever came of the KH-18 transmission? Would be great to hear the final diagnosis, if it has played itself out. In a similar situation. 

Thank you - 
Matthew


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