J/30 Class Association Forums J/30 Forum The Boat, Sails and Equipment 1981 J30 Engine

I am about to buy an 81 J30 and upon surveying the boat today we found it had a Yanmar 2GM engine instead of the 2QM15. Does anyone know anything about this change and know anything about the differences in the engines. Also is there a masthead light on the J30? We could not see any sign of one with binoculars since the mast is up. Thanks, Paul

I have 1982 381 Yanmar 2 GM (14 HP then, 18 hp for new ones) I was not aware that this is not the standard engine on all J 30s it was on all of the one I looked at, anyway great engine, reliable, easy maintenance, great access.

I think the 2GM15 is the 2QM15 with fresh water cooling instead of raw water cooling.

I have a 1984 with the 2GM as well no problems

I have a 1981 J30 hull#340 and the standard
engine is the 2GM raw watered cooled.

Also, I don't believe that a Masthead light was standard, although I do have a switch on
the DC Panel Labeled "Masthead Light".

I believe the earlier boats (and I don't know at what hull number they switched) had 2QM15s, and later boats have 2GMs. The QMs have a cast iron block, and are heavier than the GMs with an alloy block. I believe they also went to a larger prop shaft when they switched engines.

I have hull #205 with the older QM15 engine. It's fresh water cooled... which is just fine on Lake Michigan. After 20 years, I replaced the injectors just as routine maintenance. I've not had to do any other major maintenance in the 14 years I've owned the boat (knock on wood).

I don't believe the boats came with a masthead light standard. There's only a steaming/spreader light.

We have a 1981, hull #256, with a 2QM15, and the 3/4" prop shaft, (which we already replaced once).

Our boat does not have a masthead light, and does not appear that it ever was riggesd for one.

John in Halifax

Hello John,

We live in Bridgewater and are considering buying an 81 J30 from Argyle (Seaya). The boat has a raw water cooled engine. As this sounds like the same engine as your boat, we are interested in your experience with your boat's engine. What about other boats you know of? We understand from a friend that the raw water cooled engines cannot be expected to last. This is a twenty year old boat, so we are wondering.

Thanks.

Nancy H.

Like Dennis, I also believe that the 2QM15 was the earlier engine. Yanmar redesigned that engine and then renamed it the 2GM15. The GM engine was designed to reduce the vibration that's typical of the QM. I have the QM in Mondial (hull number 215). Overall, they are durable little engines. I really wouldn't worry about the mere fact that it's a raw water cooled engine. On the Chesapeake, we run in brackish water and most of them are still chugging along. You could pull the zincs (there's one in the block and another in the head) to verify that they are in good condition. Then, I'd have the surveyor look at it. If you're still concerned you could have a separate engine survey done by a mechanic.

The 2QM15 was produced by Yanmar from 1977-1980. This was a 15hp raw water cooled engine. That engine was than redesigned to be smoother, quieter, and more dependable and was renamed the 2GM. This 15 hp engine was produced between 1980-1983 and was available with both raw water cooling and fresh water, the latter being called the 2GMF. Yanmar once again improved on this engine and relaeased a 18hp model that is also available with both cooling systems. This was the 2GM20 and the 2GM20F which started production in 1983 and is still being produced today.

Hll #359 has a 2GM raw water cooled engine. It runs great but does vibrate alot at idle. Its surprising to hear from Joe that this was the improved vibration model. At idle the deck looks like jello. Its fine once its under load. Maybe a little loud. I did add a significant amount of insulation to the aft compartment that did wonders for the noise.

I did have a cooling water problem that turned out to be rust in the head and block. Soaking it with a mixture of oxalic acid and water periodically keeps the problem managable.

Alan just where did you add insulation and what type. I have a 2gm in #271 and can't imagine what the 2qm must sound like. I thought my engine was loud.

I'm amazed at the disparity of replies to this thread. It seems that everyone has a unique POV on the history of the Yanmar inboard power for the J30. It would be a great project to research this from J/Boats, and post the engine model spec for each year/ hull number to the class page.

Anyone want to place odds on finding this easily in the J/Boats production archives?

I just purchased hull #517 (1985) and have no idea which power plant it has. I have a hold back on the purchase price, awaiting sea trial of the diesel, so the diesel subject is of some interest to me.. any recommendations on what I should look for specifically when powering up in the trial? (I'll have a yard mechanic on hand for this)

Paul, you most likely have the 2gm engine and you will most likely find a sign on the engine stating so. When you check the engine out look for signs of obvious leaks which should show as stains around hose and on the block. When you start up for the first time be specific with the previous owner that you want the engine to be cold. He should not start it before you arrive with the mechanic. When you first start her up check for excessive smoke from the exhaust. My engine run relatively smoke free and its 21 years old. Also check that there is water coming out of the exhaust. You can check the temperature of the water by touching it and see if the thermostat is working. It should be slightly warm. Listen for strange noises although if this is the first diesel you have encountered they may all seem strange. Your mechanic can check the electrical system to see if the alternator is working. Check the operation of the gearbox and the ease of operation of the shift controls. Good Luck

It seems like the changeover between the 2QM and the 2GM happened somewhere in the high 200s to about 300 range for hull numbers. If you have an early boat with a 2GM engine, my guess is that the engine was replaced at some time in its history.

Anyone looking into these boats should not think of model years, instead they think of hull numbers. J/Boats and Tillotson Pearson made incremental changes to the boats at a certain hull numbers. Unfortunately, much of the ancient history of the J/30 is not recoverable. There was a fire at the TPI factory in the late 80s that destroyed most of their old records about things like this. So most of what we have to go on is reconstruction of events (like this discussion) and the memories of the Johnstones and our own long-term owners.

The main reason for the changeover seems to be the unavailability of the original engine. There is another reason, however. With a fresh water cooled engine, the thermostat is set higher (around 180 degrees IIRC) versus the raw water cooled temp of only about 140 (again IIRC). The higher temperature allows a hot water coil to be added to provide domestic hot water for pressure water systems. On the other hand, the cooler thermostat temp of a raw water cooling system is used to prevent salt from precipitating inside the engine. That's one of the reasons these engines have lasted so long.

On the issue of smoking at startup, I agree with a few caveats. The engine should start up relatively quickly if its in decent shape. The engine should not need to be turned over for a long time to build compression. But remember, this engine does not have glow plugs. Therefore if you're trying to start the engine when it's been sitting for several days in Canadian March weather, it may not start all too quickly. Also, the engine will run only as well as the fuel injectors will allow it to run. On Mondial, I know that I had a problem with both hard starting and smokiness that was due to clogged injectors. For a very nominal price, a mechanic cleaned the injectors and the engine would start up within a few seconds (again, at reasonable ambient temps).

[This message has been edited by jmruzzi (edited 03-26-2002).]

Paul C,

I ordered some of the heavy insulation from Defender. The kit had just enough to insulate the sides and back of the compartment aft of the engine. The back panel is the most important one, in my opinion, because it has small openings into the lazarette area through which sound carries aft and then forward into the quarterberths. I also insulated the wood side panels between the aft engine compartment and the quarterberths.

Another help is to get some of that sticky back padding stuff. Line the contact points of the cabinets, engine cover, and anything else that makes a noise when the engine is running. That vibration creates alot of noise just by rattling the boat.

For what it is worth, Quicksilver hull #344 has a 2QM. I am confident it is the original power plant.

BrianT
You are right. #517 has a 2GMF ("F" means fresh water cooled I presume)

Nancy, we have owned Shadow for 6 years and have had no problems with the engine other than breaking a prop shaft in the middle of Halifax harbour, and having a really difficult time getting the engine/shaft aligned. Yes, it is a 20 year old boat, with a balsa core, and you really really need to get the boat surveyed by a reputable surveyor before you make a deal. I can provide 3 or 4 names form the Halifax area (one of whom owns a J/30) if you are not sure of one in your area. Please feel free to contact me at jcolpitts@hfx.andara.com if you wish to discuss.

John

Nancy, I would like to comment on raw water cooling and engine life expectancy. I have hull #367 with a 2GM (1981). As a result of a stupid mistake on my part, I found myself needing to have the engine rebuilt last year. It was completely disassembled and I got to inspect every part on the work bench and my mechanic and I agreed that the parts were in very good condition. The only real indication of age was a small amount of scale in the cooling water passages. If the zincs are inspected and changed as needed, there's no reason that the engine shouldn't last indefinitely. Its a great engine and starts right up every time.