Hello My YSB 12 is smoking excessivly (black .. leaves a carbon trail in the water behind me) under load. This does not occur at the dock. The motor runs cool, possibly to cool. I am not shure if there is a thermostat in this motor or not. I have been trying to find a service manual for it but I have not had any luck. Any suggestions greatly appreciated. SCA
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USUALLY.....
...this is an indication of burning TOO much fuel. If it were blue it would be an indication of oil. I would have the injector checked first. I think you can get the manual through your Yanmar dealer.
...this is an indication of burning TOO much fuel. If it were blue it would be an indication of oil. I would have the injector checked first. I think you can get the manual through your Yanmar dealer.
YSB12 Black Ehaust
According to the Yanmar manual, things to consider if there is Black smoke only under load: Carbon accumulation inside pre-combustion chamber. Inspection of the opening and closing of suction and exhuast valves. Delayed fuel injection timing due to wer in thickness of adjusting shims. Failing that, consider wear of Piston rings and/or cylinder liner.
According to the Yanmar manual, things to consider if there is Black smoke only under load: Carbon accumulation inside pre-combustion chamber. Inspection of the opening and closing of suction and exhuast valves. Delayed fuel injection timing due to wer in thickness of adjusting shims. Failing that, consider wear of Piston rings and/or cylinder liner.
Thanks for the replies. I have talk to two Yanmar distributers and they both told me the service manual is no longer available from Yanmar. I suppose I will have to find a mechanic. SCA
YSB12 engine temperature
Hello SCA Also have a YSB12 on 1977 H30. There is a thermostat however it regulates to about 115 to 120 degrees. This low operating temp is used to reduce build up of deposits from the salt water in the riser and engine. Most diesels run much warmer but these are usually freshwater cooled with heat exchanger systems. Can't help with the black smoke problem, but I have been told that it can be worn or improperly adjusted injectors. good luck -- let us know. Henry
Hello SCA Also have a YSB12 on 1977 H30. There is a thermostat however it regulates to about 115 to 120 degrees. This low operating temp is used to reduce build up of deposits from the salt water in the riser and engine. Most diesels run much warmer but these are usually freshwater cooled with heat exchanger systems. Can't help with the black smoke problem, but I have been told that it can be worn or improperly adjusted injectors. good luck -- let us know. Henry
Injectors Clogged
Sounds like some winter trash (or algae) has made its way to the injector tips. If you a mechanical, pull the injectors and take them to a diesel shop for testing. They should "break" (point at which they spray diesel) at around 2200 psi. I would bet that you need new tips at a minimum, but also check your air-make sure the air intake is not blocked.
Sounds like some winter trash (or algae) has made its way to the injector tips. If you a mechanical, pull the injectors and take them to a diesel shop for testing. They should "break" (point at which they spray diesel) at around 2200 psi. I would bet that you need new tips at a minimum, but also check your air-make sure the air intake is not blocked.
Over Propped
Although is sounds like your problem is within the engine, an engine that is over propped can also cuse black smoke. Too much load that doesn't allow the engine to reach max RPMs and all the fuel you are dumping into the cylinders cannot burn complety. If you have re-propped recently or have an out-of-adjusted feathering this may be the cause.
Although is sounds like your problem is within the engine, an engine that is over propped can also cuse black smoke. Too much load that doesn't allow the engine to reach max RPMs and all the fuel you are dumping into the cylinders cannot burn complety. If you have re-propped recently or have an out-of-adjusted feathering this may be the cause.
Does anyone know if the SELOC Yanmar manual covers the YSB12? This manual can be ordered from Boat US. Thanks SCA
Clean bottom
You can get the Sealoc manual at Amazon.com. According to the title, it covers the Gm, Gm/Hm, Jh and Jh2 Series. I have a copy on the boat, don't recall it covering a YSB model, but I'll check and post if it does. Surprisingly, I bought my copy at Boat/US for a lower price that Amazon quoted ($25 vs $28). I guess those dot coms have to start making money somehow! If your bottom or prop are fouled, it will create excessive loads and cause the motor to smoke. I have read you can also get the Sealoc manual on amazon.com
You can get the Sealoc manual at Amazon.com. According to the title, it covers the Gm, Gm/Hm, Jh and Jh2 Series. I have a copy on the boat, don't recall it covering a YSB model, but I'll check and post if it does. Surprisingly, I bought my copy at Boat/US for a lower price that Amazon quoted ($25 vs $28). I guess those dot coms have to start making money somehow! If your bottom or prop are fouled, it will create excessive loads and cause the motor to smoke. I have read you can also get the Sealoc manual on amazon.com
Sealoc manual is generic
Sealoc manual is generic, and applies to the G/H/J engine series 1975-1998, however, it can still be of assistance. (Amazon.com @ $27.96 + 3.99 s/h) For example, I use an SVE8/12 series Yanmar factory manual which was on board from the previous owner, even though my engine (on a 1978 H27) is actually an SB8. The differences are minor. If you are looking for a specific item, I will be glad to look it up for you.
Sealoc manual is generic, and applies to the G/H/J engine series 1975-1998, however, it can still be of assistance. (Amazon.com @ $27.96 + 3.99 s/h) For example, I use an SVE8/12 series Yanmar factory manual which was on board from the previous owner, even though my engine (on a 1978 H27) is actually an SB8. The differences are minor. If you are looking for a specific item, I will be glad to look it up for you.
Specifically I am trying to check / adjust injector timing. I have found manuals for a YSE 12. Anybody know if injector timing setup is the same ? Thanks SCA
Injector timing
I show 12degrees nominal BEFORE TDC with an operating range of 8-12degrees actual value after procedure has been repeated several times and an average taken. Timing is adjusted by the shims (add shims to retard or remove shims to advance) between the fuel injection pump mount and the cylinder block. Note that the gasket and the copper washer of the plunger barrel must always be replaced when re-installing the fuel injection pump. I assume you are inclined towards all this, as you must remove the starter motor and get a good visual on the timing mark on the crankcase and the scale on the flywheel. Fuel injection pressure is a totally different matter, and is increased by by adding injection pressure adjusting shims below the nozzle spring holder to increase pressure.
I show 12degrees nominal BEFORE TDC with an operating range of 8-12degrees actual value after procedure has been repeated several times and an average taken. Timing is adjusted by the shims (add shims to retard or remove shims to advance) between the fuel injection pump mount and the cylinder block. Note that the gasket and the copper washer of the plunger barrel must always be replaced when re-installing the fuel injection pump. I assume you are inclined towards all this, as you must remove the starter motor and get a good visual on the timing mark on the crankcase and the scale on the flywheel. Fuel injection pressure is a totally different matter, and is increased by by adding injection pressure adjusting shims below the nozzle spring holder to increase pressure.
Thanks for the information George. I have much experience with gas engines but very limited on diesl. I will pull the starter off this evening and check it out. Thanks again SCA
You're welcome!
By the way, I assumed you know the following when checking timing position: - Set throttle wide open - Remove fuel injection line from the delivery valve. - Hold down the decompression lever - Use the manual crank, and slowly turn the flywheel by hand until the point that fuel flows from the delivery valve. - stop the flywheel from turning immediately at that point. - now check you timing mark vs.TD mark placement. - Repeat the procedure a few times to see if consistent... At least checking the timing is not very different than a gasoline engine, (except that it's still!), but to adjust it, too bad you just can't rotate the distributor body like a good old car engine, that would be far too simple... It's "shim" time! By the way, adding or removing a: 0.2mm shim = 2degrees 0.3mm shim = 3degrees Very convenient for remembering...
By the way, I assumed you know the following when checking timing position: - Set throttle wide open - Remove fuel injection line from the delivery valve. - Hold down the decompression lever - Use the manual crank, and slowly turn the flywheel by hand until the point that fuel flows from the delivery valve. - stop the flywheel from turning immediately at that point. - now check you timing mark vs.TD mark placement. - Repeat the procedure a few times to see if consistent... At least checking the timing is not very different than a gasoline engine, (except that it's still!), but to adjust it, too bad you just can't rotate the distributor body like a good old car engine, that would be far too simple... It's "shim" time! By the way, adding or removing a: 0.2mm shim = 2degrees 0.3mm shim = 3degrees Very convenient for remembering...
Hello George Just a few more questions. I went down and took a look at the motor. First I noticed I must remove the alternator... bummer. Second I assume the fuel delivery valve is the cylindrical device to the left of the oil fill (looking at front of motor) with the fuel line leading to the injector. Third does the key need to be on (to power the electric fuel pump) for the test. It appears to have two shims at the moment. I have also become suspect of the fuel and have added Valvetech fuel conditioner / cetane booster. Thanks again Scott.
YSB12 Black Exhaust
Just had the very same problem w/ my Yanmar 18 last summer on the way to the Delta. Turns out the mixing elbow for the exhaust was 80% clogged. Instaslled new mixing elbow and good as new.
Just had the very same problem w/ my Yanmar 18 last summer on the way to the Delta. Turns out the mixing elbow for the exhaust was 80% clogged. Instaslled new mixing elbow and good as new.
Answer is yes on all questions.
If, unfortunately, you have an electric fuel pump, you need it on for uniterrupted fuel supply when doing your timing check. And by all means, do check the exhaust mixing elbow first as suggested in the previous post. They have a limited life.
If, unfortunately, you have an electric fuel pump, you need it on for uniterrupted fuel supply when doing your timing check. And by all means, do check the exhaust mixing elbow first as suggested in the previous post. They have a limited life.
Re: "suspect" fuel
Pump old fuel out into jugs with a long tube on a hand pump that reaches well to the bottom of your tank and get rid of it! (change your filters if it looks particularly bad) Repalce it with brand new fuel with the additives you mentioned. Additives are preventatives, they really can't help fuel that is already become a "suspect".
Pump old fuel out into jugs with a long tube on a hand pump that reaches well to the bottom of your tank and get rid of it! (change your filters if it looks particularly bad) Repalce it with brand new fuel with the additives you mentioned. Additives are preventatives, they really can't help fuel that is already become a "suspect".
Black Exhaist
Check your exhaust mixer elbow. I Had the identical symtems and the mixer elbow was 80% clogged. New elbow solved the problem
Check your exhaust mixer elbow. I Had the identical symtems and the mixer elbow was 80% clogged. New elbow solved the problem
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