i have a ysm12 and want to replace it with a 2qm yanmar. anyone have info on hp / fuel consumption, weight , size, etc on 2qm vers ysm12?
engine repower
- Thread starter Chuck Creel
- Start date
- Status
2QM Yanmar
I have a 2QM in the S2. It is rated at 15hp. Pushes the 28 at hull speed pretty easily. Fuel burn is a little under 1/2 gal. per hour at 80% throttle. Pull it back to about 4 1/2 knots boat speed, and it burns about a quart an hour. Don't have a firm idea on the weights, but would think that the 2QM isn't much heavier than the one lunger you have. That big flywheel on the one lunger probably makes up most of the difference for that other cylinder.
I have a 2QM in the S2. It is rated at 15hp. Pushes the 28 at hull speed pretty easily. Fuel burn is a little under 1/2 gal. per hour at 80% throttle. Pull it back to about 4 1/2 knots boat speed, and it burns about a quart an hour. Don't have a firm idea on the weights, but would think that the 2QM isn't much heavier than the one lunger you have. That big flywheel on the one lunger probably makes up most of the difference for that other cylinder.
Limited parts availability on these older engines.
Chuck: Most of these older engines like the YSM & QM have limited parts availability. So you may want to think about one of the later model engines if you are looking at a used unit anyway. I think that the QM were also raw water cooled too.
Chuck: Most of these older engines like the YSM & QM have limited parts availability. So you may want to think about one of the later model engines if you are looking at a used unit anyway. I think that the QM were also raw water cooled too.
Repower
The QM is much more rugged but heavier than the later GM series. Parts very available from Yanmar distributors. My 2QM rated at 20 hp at 2400 rpm. My 3QM is rated at 30 hp at 2400 rpm. Much more power than later GM series and last longer with lower rpm and bigger displacement.
The QM is much more rugged but heavier than the later GM series. Parts very available from Yanmar distributors. My 2QM rated at 20 hp at 2400 rpm. My 3QM is rated at 30 hp at 2400 rpm. Much more power than later GM series and last longer with lower rpm and bigger displacement.
YSM12 specs
Chuck - The YSM 12 weighs 286 lbs with transmission: it's 25" long x 26.5" wide x 19" high, according to the service manual. Gear reduction is either 1.98:1 or 3.06:1 ( probably 1.98 ) It turns a left hand wheel ( prop rotation is CCW viewed from astern ) Don't have any specs on the QM20, but I think that it is a vertical engine while your YSM is horizontal, so you'll likely need more vertical clearance for the QM. I think the QM uses a right hand wheel, and with more power you'll need a new prop anyway. If the prop can't absorb the developed power you're just wasting your $$ Fuel consumption for a diesel engine is theoretically 0.45 lbs/developed HP/ hour. Under normal operating conditions you shouldn't see any significant increase in fuel consumption, but under load the QM would burn roughly 80% more fuel than the YSM. That's still not a very thirsty set-up. Don't know what the engine bed width is but you'll probably have to modify the mounts & also the exhaust. Good luck with it.
Chuck - The YSM 12 weighs 286 lbs with transmission: it's 25" long x 26.5" wide x 19" high, according to the service manual. Gear reduction is either 1.98:1 or 3.06:1 ( probably 1.98 ) It turns a left hand wheel ( prop rotation is CCW viewed from astern ) Don't have any specs on the QM20, but I think that it is a vertical engine while your YSM is horizontal, so you'll likely need more vertical clearance for the QM. I think the QM uses a right hand wheel, and with more power you'll need a new prop anyway. If the prop can't absorb the developed power you're just wasting your $$ Fuel consumption for a diesel engine is theoretically 0.45 lbs/developed HP/ hour. Under normal operating conditions you shouldn't see any significant increase in fuel consumption, but under load the QM would burn roughly 80% more fuel than the YSM. That's still not a very thirsty set-up. Don't know what the engine bed width is but you'll probably have to modify the mounts & also the exhaust. Good luck with it.
repowering
many thanks to all who replied. the cost of the enginge with all instrumentsm gear box , controls , etc is $1200.00 the engine has abt 1400 hrs on it. I am thinking of reducing vibration and more parts availability. However the hp gain im not sure if another 3-4 hp is worth it. i would only be reducing the vibration .
many thanks to all who replied. the cost of the enginge with all instrumentsm gear box , controls , etc is $1200.00 the engine has abt 1400 hrs on it. I am thinking of reducing vibration and more parts availability. However the hp gain im not sure if another 3-4 hp is worth it. i would only be reducing the vibration .
Think twice about repowering with QM series !
this engine series was last manufactured in 1980 and only in raw water cooled version. several were converted with after market fresh water conversion kits. most of these engines died because of either salt build up or internal rust blockage and or corrosion. i have one in my O'Day 30 and its a very good engine. however a few things that i have come across over the years (I've had this boat 18yrs). Ive had two heads rust thru, blockages in the block and exhaust manifold. about 5 yrs ago the second head rusted thru near a valve. i was as you and thinking of re-powering. I did luck out and i found another complete engine, sans exhaust manifold, in maine that had been converted to fresh water cooling. fortunately i was able to salvage the manifold from my old engine by boiling it out with radiator cleaner and a lot of poking to clean out the rust. most parts are still available for this engine except for the manifold. _____yanmar no longer sells this part______ and hasn't for several years. there are some cross over parts for the QM series and the Gm series but the manifold isn't one of them. check out the manifold before you proceed ahead. if its ok and/ or salvageable then i would seriously consider converting it. Sen-Dure corp in Fla makes fresh water conversion kits. I have one on mine and it seems to work very well but be forewarned that the engine will run a little hotter and it will set off the existing high temp alarm. also if you want to convert it, the cost is about 800$. after conversion engine will run at about 140deg. with the conversion i will never have to worry about rust in the internals of the engine again, because of the rust inhibitors in the anti freeze. btw this engine moves my 11,000 lb. O'day along at 6.5knots at 2200rpm with no trouble. S/V Que Pasa?
this engine series was last manufactured in 1980 and only in raw water cooled version. several were converted with after market fresh water conversion kits. most of these engines died because of either salt build up or internal rust blockage and or corrosion. i have one in my O'Day 30 and its a very good engine. however a few things that i have come across over the years (I've had this boat 18yrs). Ive had two heads rust thru, blockages in the block and exhaust manifold. about 5 yrs ago the second head rusted thru near a valve. i was as you and thinking of re-powering. I did luck out and i found another complete engine, sans exhaust manifold, in maine that had been converted to fresh water cooling. fortunately i was able to salvage the manifold from my old engine by boiling it out with radiator cleaner and a lot of poking to clean out the rust. most parts are still available for this engine except for the manifold. _____yanmar no longer sells this part______ and hasn't for several years. there are some cross over parts for the QM series and the Gm series but the manifold isn't one of them. check out the manifold before you proceed ahead. if its ok and/ or salvageable then i would seriously consider converting it. Sen-Dure corp in Fla makes fresh water conversion kits. I have one on mine and it seems to work very well but be forewarned that the engine will run a little hotter and it will set off the existing high temp alarm. also if you want to convert it, the cost is about 800$. after conversion engine will run at about 140deg. with the conversion i will never have to worry about rust in the internals of the engine again, because of the rust inhibitors in the anti freeze. btw this engine moves my 11,000 lb. O'day along at 6.5knots at 2200rpm with no trouble. S/V Que Pasa?
My YSM 12
I bought a ¡¦78 Catalina 30 several years ago with a seized YSM12¡K.I got a very good deal on the boat. I decided to pull out the YSM and get it rebuilt by a Diesel mechanic ¡V he took her apart, replaced all the bearings, piston, rings, head, injector nozzle ¡V almost everything. It cost me about $3.5k with parts and labor. Parts were not that difficult to get but some took a few weeks to arrive. After I installed the engine (did that myself) I thought about adding a fresh-water kit to the cooling system but that was turning into a bigger project that originally planned. I instead plumbed a fresh-water bypass (plumped in from the boats portable water) ¡V the bypass Y valve is located between the raw water seacock and raw water pump. I flush the engine out after every run (the boat is in salt water) and for my purposes, I found this to be better than the fresh-water kit because I cover not only the engine but the exhaust system as well. A fresh-water cooled engine is better, don¡¦t get me wrong ¡V but the YSM12 was designed for raw water. I give here a vinegar flush once a year too. So sometimes a rebuild is maybe a bit easiers¡K 5 years and she starts up on the first try every time! (knock-on-wood) ƒº Rob
I bought a ¡¦78 Catalina 30 several years ago with a seized YSM12¡K.I got a very good deal on the boat. I decided to pull out the YSM and get it rebuilt by a Diesel mechanic ¡V he took her apart, replaced all the bearings, piston, rings, head, injector nozzle ¡V almost everything. It cost me about $3.5k with parts and labor. Parts were not that difficult to get but some took a few weeks to arrive. After I installed the engine (did that myself) I thought about adding a fresh-water kit to the cooling system but that was turning into a bigger project that originally planned. I instead plumbed a fresh-water bypass (plumped in from the boats portable water) ¡V the bypass Y valve is located between the raw water seacock and raw water pump. I flush the engine out after every run (the boat is in salt water) and for my purposes, I found this to be better than the fresh-water kit because I cover not only the engine but the exhaust system as well. A fresh-water cooled engine is better, don¡¦t get me wrong ¡V but the YSM12 was designed for raw water. I give here a vinegar flush once a year too. So sometimes a rebuild is maybe a bit easiers¡K 5 years and she starts up on the first try every time! (knock-on-wood) ƒº Rob
Rob; my main point!
My main point is that a very critical part on the QM is no longer available from yanmar. and the newest of these engines are 27 years old. as i said the used engine i bought already had the exhaust manifold cannibalized off it. that's why i recommend checking out the manifold very carefully. if it goes it would be almost impossible to find another that's in decent shape. i constantly come across people looking for this part.
My main point is that a very critical part on the QM is no longer available from yanmar. and the newest of these engines are 27 years old. as i said the used engine i bought already had the exhaust manifold cannibalized off it. that's why i recommend checking out the manifold very carefully. if it goes it would be almost impossible to find another that's in decent shape. i constantly come across people looking for this part.
- Status