Yanmar 3QM30 with Kanzaki KH 18 tranny

[AZ-Oldguy]

Hello Cruising Forum members.

I have been lurking on this site since last April, like a sponge, learning tons, reading the digest start to finish almost every day. I have learned a lot.
I have made an offer on a 35 foot, 1980 model cruiser, and am in the survey process. I hired a well recommended shop to check out the motor and transmission first of all, as that is my area of greatest concern about the boat.

Some of the news was good. Some not so good.
The motor is a Yanmar 3QM30. As that particular motor wasn't produced after 1982-3, we can assume it is the original motor as the boat actually wasn't launched until 1983. It has under 1600 hours. Even with ice on the deck, and not started for days, it fires up almost instantly. Runs sweet, comes right up to temperature, levels off at 175. Unlike most of these 3QM30s, this one is not raw water cooled, has a very robust and huge heat exchanger, and two pumps on the front of the engine, one belt driven, one driven off the crank. That is the good news.

There are three areas of concern with this engine. The water pump">Raw water pump, crank driven, is leaking through the weep hole, and should be replaced right away. This should not be a problem. The pump should be easy to find. The manifold which has salt water running though it, is badly rusted, and also should be replaced soon as it has the potential to wreck the engine, as well as sink the boat . The mechanic suspects rust is probably from the inside out. The exhaust mixer, where sea water from the heat exchanger enters the exhaust system, which attaches directly to the manifold with pipe thread, is also bad, has a crack, and is probably rusting from the inside out as well. (I don't know the proper name of this piece.)

I am told by the mechanic that these two latter items are going to be hard to find. I would appreciate any information about where I might source any of them.

Even more worrisome is the Transmission, Kanzaki KH 18. When we put the boat into gear she ran well, and pulled hard on the mooring lines in reverse, but in forward there is a very unpleasant knock/clang noise that actually shakes the motor and the drive line behind the transmission. The Mechanic doing the survey is pretty sure we have isolated the problem to
the transmission. The Transmission shop says that it can be difficult to get parts for that transmission, and some parts, like the shift fork, are not available.

I know the easy solution is to just re-power, and am told I could do that for about $10,000, which in the long run might be the cheapest way to go. However I am stretched at the moment, buying this boat, and don't want to pass her up if we can fix these issues and the rest of the boat is good. The owner is willing to work with me, and we will do what we have to do to make this deal work, so long as it remains a good deal for both of us. If there is a possibility to rebuild the tranny and get the parts I need for it, and for the engine, I think we can get some good years out of this power train.

So I am happy to hear the thoughts of this list, and I know the responses will be all over the place. but hopefully I will hear from some who have actual experience with a Yanmar 3QM30 and or a Kanzaki KH 18 tranny. I would be very interested to hear from anyone who has, or might know where I could get the parts I am looking for.

Sorry if this post is rather long for a first post. Thanks for your time.

Cheers, Glenn

[limte]

Glen,
I just saw your post, so I may be quite a bit late in response to your question. I had a Yanmar 3QM30(F) in my boat until this fall, when I replaced it with a Beta 38. The Yanmar was still running fine, started without difficulty, and was very reliable. However, as you note, parts are beginning to be a problem. The exhaust elbow is still available, but the manifold is not, unless you can find one lying around unsold (unlikely). I also had the Kanzaki KH-18 gearbox, and as you noted, parts can be very difficult to obtain for that gearbox. I decided to re-power sooner rather than later, particularly because I wanted to avoid common rail fuel systems, and the Beta 38 is still available without the common rail system. In the future, it is likely that most diesels will change over to common rail, a more complex system, relying on electronics rather than mechanical components to deliver the fuel. I think your estimate of re-powering is a bit low; it is probably more in the range of $12,000 to $14,000 including parts such as new prop shaft, coupling, propeller, etc. I was able to sell my Yanmar for $1,500, so that eased the sticker shock of the new engine a bit.
Regards,
Bob S

[AZ-Oldguy]

Hi Bob, thanks for the reply, for now we're are sticking with the engine and tyranny we have. We think we're have found the parts We're needing at acceptable prices, and feel reasonably sure that there is a lot of life in this engine. I would like to hear more about how your repower went, did the person buying your engine get it for parts?

[limte]

Glenn,
I sold the engine as a working engine, and as you suggest about your Yanmar, it still has a lot of life in it. As I noted in my last post, I had other reasons for changing engines besides age and parts availability. And speaking of age (my own that is), I figured I needed to do the engine change while I still had the interest and energy to deal with it. I've got the engine in place now and will be working over the winter to get everything connected and working properly. I should note that the approximate cost I gave of the new engine and related parts is for an owner install; if you hire a yard to do it, depending upon possible issues with engine beds, exhaust, etc. it could cost double that amount.
Regards,
Bob S

[charliehows]

sounds similiar to the problems i had with my 2qm20 1979 engine when i got it - the trans wasnt knocking but the forward clutch slipped so badly the boat could only make about 1 knot if there was no resistance. The engine was raw water cooled so there were no problems with cooling systems, but i did pull the pump and replace the seals as a precaution - quite expensive parts but a relatively easy procedure.
fyi pulling the gearbox in situ is fairly easy depending on the layout of your boat - for mine, i drilled a 1/2 inch hole in the cockpit floor above the guessed lift centre of the eng., set up a steel beam and block/tackle across the cockpit and fed an 8mm wire through the hole using cable clamps and chain to lift the engine, turn it sideways and then remove the gearbox. I dismantled it as far as i could and took the clutchplate cluster to a good mechanic who replaced both clutches (by the way - i got into a couple of annoying sailing conundrums because i was too stupid to realise that the boat manoevres pretty well in reverse if you dont have a usable forward gear)
As for the engine, in the last 5 years ive replaced the starter, headgasket, all the fuel system hoses, taps and sealing washers, lift pump but nothing more than you would expect in general maintenance, and its still a good engine.
good luck.

[Terra Nova]

Terra Nova also has the Yanmar 3QM30, a great engine with low hours.

When I first bought the boat, the starter was intermittent, so I shopped around for a new one. $1,000 was quoted to me for that tiny little thing! So I asked about a rebuilt and was quoted $600 plus $300 core charge (I wanted to keep my old starter, to overhaul as a spare).

Months later I saw an ad on a West Marine bulletin board for a used 3QM30 @ $2500. I called just to see if he'd sell me only the starter (HA!). A couple months later I saw an ad in the San Diego Log @ $1500, with the same area code. I called and asked why the $1000 price reduction (he discovered a cracked head) and he still wouldn't sell me only the starter. So I left my phone #, saying I'd buy the whole thing for $500 if he couldn't sell it.

He called me 3 weeks later and delivered it to me for $500 total. Included were a complete set of new (spare) injectors, new steel injector lines, some other spare gaskets and an extra manual. And of course a complete starter

[AZ-Oldguy]

Terra Nova, that sounds like a very good deal, I wonder why he didn't sell you just the starter. Are you planning to keep the rest of that engine for parts? are you interested in selling any of them? What kind of fuel consumption do you get on that engine per hour?

[Terra Nova]

I don't remember the fuel figures. And I hadn't thought to part it out. Just figured I'd keep it as a parts motor. PM me if there is anything specific you are interested in.

These are low rpm engines compared to the G-series. Way better.

[AZ-Oldguy]

Terra Nova, I will definitely keep in touch with you as I begin work on this engine and transmission. I have been quite pleased with the engine as you say, low rpm. We went on a sea trial and it ran great, probably motored for over half an hour. Also took it up the canal in Seattle to get it hauled out as part of a survey we motored both ways, maybe 45 minutes each way and it just ran beautifully. I'm really excited about the boat and we are going ahead with the purchase in the new year. So I'm sure I'll be in touch. There are things like the injection pump which are pretty rusty on this motor. We will be replacing the exhaust elbow, the raw water pump, and the manifold. The seller deducted the value of those parts from the purchase price after we had done the motor survey. Thanks for replying, Glenn

[sailorchic34]

Agree with TN, that the QM are far more robust then the GM. Probably need to change the zinc in the back of the head too (I recall one being there, even on the fresh water cooled QM's).

The raw water pump, might just need a new water seal (few $$). It's possible that all you need to do is remove the pump, remove the bearings and shaft and clean the deposits around the water seal. minerals buildup around the water seal. Of course installing a new water seal then is smart, but sometimes the old one is still good enough.

[AZ-Oldguy]

SC, does that zinc just bolt on on the back of the head? I hadn't noticed one there. I will be trying to repair and rebuild as much as I can rather than just buy new units.. The surveyor suggested replacing the impeller on an annual basis.

[rbyham]

I have a the very same drive train in my 1978 Bombay. Owning since past February I am now very confident in both engine and trans. I would recommend getting hold of manuals. They are available for download on the Internet though I have lost the link. Also there is at least one old gent in WI somewhere who will sell you a rebuilt KH18 for about $900 and your old one should your trans ever die. I think the place is called Shipyard Marine. The word I hear on those units is they are bulletproof. Bbe aware the trans does have a filter on the rear. I would recommend taking it out for inspection and cleaning. I found some fine metal flaks which were cleaned and filter simply reinserted. I also changed atf trans fluid a couple times in rapid succession as my boat when bought had not been run for 3 years. Have since run about 150 hours with zero problems. As far as starters I suspect there may be some cheaper options than yanmar but mine works fine after disassembly and brush cleaning... I am RWC and find summer temp steady at 165 which is a tad high. I have changed one zinc. There are two on front of engine. Yes there my be one on back as well. Mine were both completely toast.

[Woody]

We have a spare KH18 and would like to sell it. Get in touch if you're interested.

[AZ-Oldguy]

Woody, did you get my 2 personal messages?

Sent from my XT1053 using Cruisers Sailing Forum mobile app

[Archaeologistt]

Originally Posted by Woody

We have a spare KH18 and would like to sell it. Get in touch if you're interested.

G'day, I'm looking for a 3QM30 and gearbox, or just the gearbox as I already have an engine that I'm prepared to recondition.

Your KH18 is what I'm looking for if its still available …