Yanmar 3QM30F

[msoneji]

Hi All,

I am looking to replace the Atomic 4 in my Pearson 10M with a diesel. I am able to get a Yanmar 3QM30F in a dis-assembled condition for < $1000 with all the parts and a put-it-together manual. The engine timing case needs repair/welding as it has a hole (?) I am a technically savvy engineer but new to boats and diesel engines. At this time I have time to spend on putting together the engine with some help.

Does anyone have some advice? Is this a good idea? Hs anyone replaced a A4 with 3QM30F? What is the difference between a 3GM30F and a 3QM30F. I guess 3GM is newer.

Also I cannot find the drawings or any technical information on the 3QM from the Yanmar site (very poor website site when it comes to technical information on current and past engines). Can anyone help me with those or point me to the place I can get them?

I am located in the SF Bay area, CA. Thanks.

[Alan Wheeler]

My first question would be, why the hole in the cover???

[msoneji]

Alan,

The answer to that question was "the hole is caused by raw water "ocean water" leaking on the cover and not fixing the broken clamp
or hose or what ever caused the drip."

[never monday]

run fast and far......

The QM will be heavier and larger than the AT4. Parts are available for the QM but supplies are dwindling with time. That engine has been out of production for about 25 years.
Hold off and fins a GM series. It'll be a much easier repower. Also, you don't need 30hp to replace the AT4. In a Pearson 10M 15-20 will do the job nicely.

[msoneji]

Never Monday,

Thanks for the message. You may be correct on that the 3QM will be a bit too large in size for me.

BTW I also can get a 3GM30F with around 1500 hrs and in working condition for $3000 locally. I just can't justify $3K+ labor of say $4K to put it in. The $7K expense is not worth it I feel. particularly since my AT 4 is working fine.

[Inlet Marine Services]

The 3gm30f is alot better deal and alot newer then the 3qm. The 3qm was the first 3 cylinder Yanmar marine engine made between 1975 and 1979,in 1980 the 3gm(f) was made in 1982 and in 1983 the 3gm30f was made until I think 04. The new model is 3ym30. The 3gm30f is 27hp and a great motor going over 5000 hrs easy.

[Liunatic]

Lookin at a C&C 38 with a 3qm on board now whats the approx. cost to rebuild or drop in a rebuilt one. Does anyone no what he replacement is for the 3qm?

Liunatic

[a64pilot]

If the A4 is working fine, why repower?

[sammyo]

I have not had trouble fining parts for a 2QM20 which is of the same era. Whether that engine is worth the trouble?

[sailorchic34]

Here I go being contrary again...

In my mind the 3qm30F is overall a better engine then the 3gm. Its heavier, lower reving. Very forgiving. Yes parts will be an issue. But a new rebuild of a 3qm should give lots more miles then a 3gm30f which is lighter construction and higher reving.

If you have all the parts with new rings, bearings, etc. then go ahead and rebuild the 3QM30. Putting an 3gm or 3qm together is a matter of a few days, once all the machining is done. Then cleaning the block (soap and water), coating the cylinders with oil to prevent rust and then do some zen mediation as you assemble it. Its pretty easy to build. I hear even some blondes chicks can build them.

Watch out for the special tools you'll need. I found that a small metal oil filter wrench makes a dandy ring compressor.

Me I would put it together in the cockpit of the boat as the weight of the finished engine will be a wee bit. Use 2x8's laid across the cockpit with drop cloth under engine. You can use the boom with the main halyard connected with rope and shackels around the hoist point on the boom. The halyard carries the weight. Then use a comealong to raise the engine and a boomvang to pull it into the cabin. Getting the engine bed situated will take some time of course.

Parts for the 3qm tend to be pricy. Though some of the parts for the 3gm sting a bit too.

[Jon Neely]

Our 3qm is in very good shape but our water pump">raw water pump is starting to weep. After trying find a complete replacement which from my research is impossible next best thing is a incomplete rebuild kit that cost $800 not including the main shaft for the impeller that I need machined. Upon these findings I started to look at other prices of parts that a 30year old engine might need in the future (starter, fresh water pump, exchanger, fuel pump, injectors) my list topped 8 grand before I stopped. Come September we will be repowering with a beta 38. Half the weight, half the size, better fuel economy and more hours power. $9000 for the engine, probably be around 13 after I install it myself. Makes sense to me, but thats just me.

[maine50]

I have a 3qm also in a C & C 38 that powers it fine. Its probably overkill for a Pearson 10m but not to much as its 32HP. A heavy engine but practically tough to destroy. (my C & C is also for sale- Milford, Ct) I have had A4s before and the A4 will be much smoother. If you havent had problems why change?

[Terra Nova]

This thread is from 2008. So I wouldn't wait long for a reply on the A4.

But I also have a 3QM30. When I bought the boat, it had the famous intermittent starter issue. It was a reminder that I should have a spare starter onboard. The cheapest brand new starter was quoted to me at nearly $1,000! A rebuilt was quoted at ~$700 IIRC, PLUS a core charge, which would make it almost as costly as a new one.

In West Marine one day, I saw an ad on their bulletin board for a used 3QM30, complete, for $2500. I called to see if he'd sell me the starter for $500. Nope. He was certain he could sell the whole thing for much more. Still no spare starter.

Months later I saw an ad in The Log, 3QM30 for $1500, with a familiar area code. I asked why so much cheaper? A cracked head was discovered. Would he sell me the starter for $500? No. The ad had JUST come out, that day. So I left my #, in case it didn't sell.

Weeks later he called. I bought the complete spare engine & trans, including service manual, brand new spare set of injectors and injector lines and a bunch of new gaskets, DELIVERED for $500.

[Inlet Marine Services]

Lets talk about Yanmar engines. The 3QM30(raw or fresh ) was made from 1977-1980 then in 1980 came the 3GM(F) and in 1983 came the 3GM30F which was made until 2004. From 2004 till present we have the YM series engines. The QM engine are getting 30 plus years old and Yanmar is not producing many of the parts. If the engine has spent its life in fresh water then there is still some life to it, but if its spent life in salt water then a repower might be the best option. Since this motor was 33 Hp then I would replace with a 3JH5 40hp engine or depending on the size of the vessel you might be able to get away with a 3ym30 30 HP, big difference in a lake then in the Pacific NW with tides. As a Yanmar dealer I would not recommend rebuilding any QM series engine. Since Yanmar is territory orientated contact your local dealer for pricing. I can sell in WA,OR,ID and AL.

[Cheechako]

IMHO the QM was a superior engine to the lighter weight GM series. The problems with the GM series are well documented. However, you have a basket case engine there. You really don't know what's wrong with it, how much it needs etc. If I were you I would price complete piston sets, head rebuild, Boring, and peripherals and then decide if it's worth it. It likely isn't.
If I remember right the QM is a lot closer to being 30 hp than the GM.