Yanmar YSB12 - Rebuild or Replace

[Thomas H. George]

I have a 1978 Hunter 30 which I love but the original engine - Yanmar YSB12 - overheated last week when the water cooling failed. I can still start it so maybe it can be repaired. If this turns out to be a major expense perhaps I should consider replacing it. I am looking for advice in either direction.Case for Repair: I bought the boat five years ago and until now it has been perfectly reliable and can push the boat a 6 knots when needed. I don't use it a lot - just in and out of harbours and, occasionally, when becalmed in hot weather - and last year the total consumption of diesel fuel was 4 gallons. If the repairs are not too expensive, why switch?Case for Replacemnet: What if it is not so reliable after an expensive repair? It has always been a concern. Its a one cylinder engine so there is considerable vibration. It is very difficult to shift the transmission. There is no instrumentation, just two idiot lights placed down where they are hard to see. You have to be a contortionist to read the gauge on top of the fuel tank.I would appreciate any comments and suggestions.Tom Georgetomgeorge@spininternet.com

 

[Butch]

rebuilt

I just went through a similar situation. Motor quit. 1979 Hunter 30 with YSM12. Rebuild was $2500. Repower was from $6000 to $8000. I decided that although I really wanted the extra power, I would opt for the rebuild. Rebuild consisted of new piston and sleeve and almost everything else but the crank which was in great shape. When all was said and done, it starts and runs like a new one. I think I made the right decision when I look at my checkbook after all it is a sail boat not a power boat. I had already added a water temp guage, not sure what else you might need.

 

[Royce]

Parts?

I had a yse12 in my 76 h30. The oil pump housing was worn and the part was obsolete and unavailable. Ihad a bushing machined and that solved the problem for a long time, but when the oil pressure again began to become somewhat intermintment, I decided I was tired of keeping a watchful eye on the oil pressure and always wondering what if it failed again in an inopportune time - so I made the decsion to repower. I found a brand new 10 year old Vetus in the paper. It was purchased and never installed. Got a great deal and the whole repower was under $3500 in parts.Good luck,Royce

 

[John Thomas]

Don't do it!

I have the YSM 12 in my H30, and I would take any excuse to replace it. It's getting hard to find parts for, and the vibration due to its 1 cyl horizontal design is horrendous. I fear that it will someday break loose from its (new) mounts and flog the whole boat to pieces!It IS a reliable engine, no doubt, but wouldn't invest much to keep it running. If new is too costly, I'd look around for a used Yanmar GM2, or a Universal, the little 3 cyl that makes 20 HP.

 

[PD]

YSB12 question

I have a YSB12 on my H30. I regularly check all bolts on the engine as it rattles so much I have found the water pump and the alt bolts loosen with time/use. Also, I change the oil very 25 hours (sounds extreme, but it is easy to do).My engine was once sunk in salt water for about an hour due to a faulty seacock. It was washed with fresh water and flushed with 2 oil changes immediatley and spayed down with WD40 (plus a new starter and alt). Anyone know if this will effect my engine in the long run? So far it seems about the same.

 

[Ian McGain]

CHECK WATER PUMP

I have a 1979 Hunter 30 with YSM12.Last season I had a constant overheating problem every time I went out.You said your engine starts- first take off the water pump. Replace the impeller and the brass screws holding the cover to the water pump. break these screws first with a clamped down vise grip to avoid stiping the screw head. This a couple of bucks. Next replace the paper gasket and add perma tec#2 between the pump, and both sides of the gasket.Now the important part- shine and reverse the water pump cover. you will see a grove worn in the inside cover by time. bolt the thing tight and replace the two belts if worn.Fire the engine up and always make sure you are pushing water out the stern. Also if you have not replaced the mixing elbow, this is a failure waiting to happen. These three pieces will cost about $300-$350 but beats a $450 tow by Boat US. This is one-half day fix. The half day is pulling your woodwork apart to get at the rear of engine- this is on the aft starboard side and part of the wet muffler system.Good luck