9.2C Repower

[capcass]

I am in the process of re-powering my 1982 9.2c. The original engine is a Yanmar 2Gm with an aftermarket (Sendur) freshwater heat exchanger cooling system. I realized that the engine started developing blow-by last year when it blew he dip stick out of the block, coating the starboard side of the engine compartment with oil and filling the cabin with smoke. The engine would consistently stall at idle and this year the situation worsened, with the idle only holding at 1100 rpm or higher. This resulted in several near misses in docking situations when the engine would stall between shifting gears while backing into my slip. I removed the transmission, alternator and belt- driven water pumps after lifting the engine from the engine compartment to the floor of the walk through to the aft cabin and used two block and tackle boom vangs rigged to a boom extension arm which I had made to lower the outboard to the dingy from the rail. This arm is supported on the aft end by the main halyard and I rigged an additional spinnaker halyard as a safety for the additional weight of the diesel. I used this arrangement to gradually pull the engine to the aft birth and hoisted it through the aft hatch, over the rail and on to the dock. This was a very efficient arrangement and I only needed help lifting the engine from the engine compartment to the adjacent floor and then into my car.

I am replacing the engine with a Yanmar 2GM20F which is rated at 18hp versus the 13hp of the 2GM model. Does anyone have any experience with this upgrade and did you have to re-pitch the prop? I have a 3 blade sailboat prop on the boat now, but am not sure of the size or pitch. Any ifo on the upgrade installation would be greatly appreciated.
Thanks,
Capt. Gary Cassidy, USCG Master
1982 9.2C "Windchaser"

 

[BobM]

There is a free prop calc program that you can use to see where your are. You need to know some info about the engine and the transmission, but it will provide an approximation of it. I found a number of 18 hp @ 3600 rpm for the 2GM20. The prop may have the pitch and size stamped on it.

http://www.alberg30.org/maintenance/MechanicalPropulsion/Propeller/propcalc.xls

 

[capcass]

Thanks Bob. What engine/prop do you have in your 9.2A?

 

[capcass]

Unfortunately the link didn't reveal the full calculator progrm?

 

["SevenSundays"]

Through the hatch in the aft cabin?

What a great idea! I'll remember that when my turn to repower comes.......

 

[BobM]

Do you have excel?

Unfortunately the link didn't reveal the full calculator progrm?

If you don't have excel, you can probably open it with the open office equivalent.

I have a 2QM15 (14hp) with a 16RH9 prop (stamped on the hub). which is 16 inches, right hand rotation, 9 pitch, with 2 blades. I can achieve 5.5 knots at 2800 rpm, which is a little underpowered. However, some of the underpower is probably just age. I was just aboard Garyllingers 9.2C that he repowered with a 2cyl 16hp engine (Beta) and he had no problems hitting 7 knots, but rpm was a bit low for correct operation of the engine (13 inch 2 blade).

The prop calculator says I could run a 12 pitch and I have a 12 pitch Martec folder, but I don't know if I want to experiment this season and deal with changing it in the (60F) water.

 

[Calypso]

I have a 3gm30 with a 14 x 11 pitch and can do about 6.5 knots or so at around 3000-3200 rpm. I could use a little more prop still. 15 x10 or 11 maybe? My prop was a 14 x 9 and the motor could easily over rev and I could only do about 5 knots. Prop shop said they could only change it to an 11 pitch so I went with that.

 

[capcass]

Thanks for all the replies. Always good to get comps from others with the same or similiar vessels. I'm not sure what size or pitch the prop I have now is, but it is a 3 blade and I can achieve about 5.5 kts @ 2400-2500 rpm with the 13hp 2Gm. Recently I've had trouble getting full 3200 rpm due to low compression, I assume. The 18hp 2GM20F would most likley need a greater pitch, but I'll probably wait until the fall when I haul the boat to have that done. I should be picking up the engine tomorrow, so I'll be installing this, 4th of July weekend. Not exactly the holiday weekend I had in mind. Hopefully there won't be any fireworks going off aboard when I crank he over!

 

[boatguy30]

Exhaust!!!

Make sure to change the exhaust!! The S2 exhaust is a disaster. I have a 1982 with the 2GM. The exhaust reduces to maybe 1"5/8" after the muffler then loops up then down then up again behind the bunk. It should have only one loop and be 2" the full run. I just bought my boat in April, but I plan to change in the near future. The engine should do 3600 rpm and mine will only do a touch over 3000 with a 15*9" three blade. I'm certain the exhaust is the main issue. Also the fuel filter/ check valve assembly leaves something to be desired. I think the best way to do the exhaust is to run out the staboard side above the cockpit drain. Other experiences are appreciated!

 

[capcass]

Exhaust

Make sure to change the exhaust!! The S2 exhaust is a disaster. I have a 1982 with the 2GM. The exhaust reduces to maybe 1"5/8" after the muffler then loops up then down then up again behind the bunk. It should have only one loop and be 2" the full run. I just bought my boat in April, but I plan to change in the near future. The engine should do 3600 rpm and mine will only do a touch over 3000 with a 15*9" three blade. I'm certain the exhaust is the main issue. Also the fuel filter/ check valve assembly leaves something to be desired. I think the best way to do the exhaust is to run out the staboard side above the cockpit drain. Other experiences are appreciated!

Interesting you should mention this, as I looked very closely at this today in serious consideration of changing it. I hesitate, however, to alter an arrangement that has apparently worked well for nearly 30 years. The double loop you refer to appears to be another way to prevent water from backing up into the engine, especially without the reverse mixing elbow. I do not think that the exhaust is the main problem with mine, , because the water flow out the exhaust like a fire hose and there is also no overheating, which would indicate a restriction.

 

[garylinger]

Re: Exhaust

When I re-powered this spring with the Beta-Marine 16, at the recommendation of the engine distributor, I replaced the smaller exhaust (hose and water lift muffler) with a 2 inch system. I kept the same loop configuration. Other than needing to change the prop (currently overpropped and only able to reach 2900 rpm) it all seems to work very well.

 

[BobM]

Be sure to stretch!

Thanks for all the replies. Always good to get comps from others with the same or similiar vessels. I'm not sure what size or pitch the prop I have now is, but it is a 3 blade and I can achieve about 5.5 kts @ 2400-2500 rpm with the 13hp 2Gm. Recently I've had trouble getting full 3200 rpm due to low compression, I assume. The 18hp 2GM20F would most likley need a greater pitch, but I'll probably wait until the fall when I haul the boat to have that done. I should be picking up the engine tomorrow, so I'll be installing this, 4th of July weekend. Not exactly the holiday weekend I had in mind. Hopefully there won't be any fireworks going off aboard when I crank he over!

Be sure to stretch your back before you start moving the engine. Gary just did his and luck for him his son is into weight lifting. They really had to just muscle it down that narrow passage to get it into place. Good luck.

 

[capcass]

Re: Be sure to stretch!

Thanks for the word of caution. I have had back surgery twice and rotator cuff surgery once, but I to have two weightlifter sons lined-up to lift the engine out of the car tomorrow morning. The hoist arrangement I used to take the engine from the boat through the aft cabin should minimize the lifting until we need to move it from the floor to the engine bed.
I'm hoping not to have to remove parts. We'll see how it goes tomorrow. Maybe I'll post some pictures of the process.
Gary Cassidy

 

[garylinger]

Re: Be sure to stretch!

When I removed my old Yanmar and then installed the new Beta I didn't think either would fit through the aft cabin hatch. The hardest part (that required the most muscle) was wiggling it above the galley area (sink and ice box). If you are able to go in through the aft cabin then you might have an easier time of it. Placing the new engine on the stringers was actually easier than I thought it would be. If your new motor mounts align with the old then that is another major advantage. I had to drill new holes after I roughly aligned the things and that was hard to do because I couldn't get around and under the starboard side with the drill without moving the engine after marking where to drill. I also had a hard time fitting the wrench in to insert and tighten the lag bolts.

 

[capcass]

When I removed my old Yanmar and then installed the new Beta I didn't think either would fit through the aft cabin hatch. The hardest part (that required the most muscle) was wiggling it above the galley area (sink and ice box). If you are able to go in through the aft cabin then you might have an easier time of it. Placing the new engine on the stringers was actually easier than I thought it would be. If your new motor mounts align with the old then that is another major advantage. I had to drill new holes after I roughly aligned the things and that was hard to do because I couldn't get around and under the starboard side with the drill without moving the engine after marking where to drill. I also had a hard time fitting the wrench in to insert and tighten the lag bolts.

I got the new engine into the boat today through the aft hatch with little difficulty using the main and spinnaker halyards attached to two block and tackle boom vangs. We hoisted it from the dock over the rail, when the attachment fitting for the dingy motor extension arm let go, giving us a tense moment, but with all the guy lines and redundancy no damage occurred. We lowered it to the aft berth deck. Then my son and I muscled it to the walk-through and set it on wood chocks so I could finish running the new exhaust hose as a final step before moving it to the engine bed. I can't imagine having to lift this 275 pound engine over the galley.

The 2GM 20F has the same mount pattern as my previous 2GM, so now new holes should be needed. One hitch prevented me from having time to move the engine to the bed today though. I had to remove the aft engine mount brackets to get the engine through the hatch. No big deal, just two bolts each., but when I went to reattach the port side bracket after getting it into the boat, the top bolt stripped. It appeared that the bolt had been heli-coiled in and tightening the bolt pulled the heli-coil out, so I spent the afternoon chasing down the right size tap to replace the bracket securely with an over-sized bolt. Fortunately one of my dock-mates is a machinist so he helped me track it down. Sure makes me nervous about the rest of the re-build though.

In all the fervor to get the project on it's way to completion, I neglected to take pictures. Hopefully I'll have her installed, aligned and running by Sunday. If anyone has pictures, description or schematic of 2Gm20F hot water heater hose routing, please let me know. I had a Tartan 28 with the same engine and engine heated hot water, I just can't remember the arrangement.

Thanks,
Gary Cassidy

 

[BobM]

Congratulations on getting the tough part out of the way! You actually were able to drop it into the aft berth through the aft hatch? Isn't it only about 2 x 2? Wow.