jiris
Member
In your list you have one point missing: TIMING. If the pump timing is not right, the engine won't work too well and in extreme case it won't fire at all. Worth checking, the timing can move easily.
Yanmar YSM 8 starting
- Thread starter S2Jimlad
- Start date
alexey
New member
What is "pump timing"? How do you tune it?
alexey
New member
I'm still struggling to bleed the fuel system. Replaced the whole primary filter, because I wasn't sure the old filter seals were good (and not leaking air in).
I went through the bleeding process two times, including the injection valve inlet, while cranking with decompression lever. I was surprised to find some more bubbles at the secondary filter at the last bleeding round. I thought I got rid of bubbles at the first round.
How many times should I do the bleeding? How do I know if it's enough?
The engine starts and struggles reluctantly for a minute, and the dies. It dies right away with higher RPM. The winter haul out is coming this Saturday, it would nice to get there on its own power.
I went through the bleeding process two times, including the injection valve inlet, while cranking with decompression lever. I was surprised to find some more bubbles at the secondary filter at the last bleeding round. I thought I got rid of bubbles at the first round.
How many times should I do the bleeding? How do I know if it's enough?
The engine starts and struggles reluctantly for a minute, and the dies. It dies right away with higher RPM. The winter haul out is coming this Saturday, it would nice to get there on its own power.
RichardS
N/A
I don't know your specific engine, but if it's not self-bleeding which it appears not to be, then you probably have to keep bleeding until there is no air in the fuel line so no bubbles when you crack open the injector unions and manually pump the lift pump. If air keeps appearing even when you are sure that you have removed it already, then there must be an air leak somewhere, presumably before the pump.
Can you see any trace of fuel leaking out anywhere in the lines? Possibly just a slight dampness or weeping rather than actual dripping fuel.
Richard
jiris
Member
Yep. That is what I meant. The pump shaft should be connected by a coupling of some description. There are usually 2 bolts on one side going thru crescent slots on the other. If they slip - you have a problem.
garymalmgren
Active member
Pump Timing adjustment.
Here is link to a general information site on your engine.
General information
Not 100% correct but some useful information
The Yanmar YS engines...
I ran out of fuel.
After that the engine was hard to start. It cranked over furiously, but took ages to fire up.
Bled the fuel 10 or more times.
Then I read in the above General Information site
“resetting the governor linkage at very frequent intervals. If the engine dies at low revs, and will not start, ”
So, I gave it a go and it solved the starting problem right away. I highly recommend this.
However the instructions in the manual are a little confusing. (page 38)
YSE YSB 8/12 HP manua l https://www.sailingthanksdad.com/documentation/Yanmar-YSE-YSBServiceManual.pdf
I have rewritten the process resetting the linkage and will add it as a POF here.
This requires limited tools and is (a very rare) 5 minute job.
All the best
gary
Here is link to a general information site on your engine.
General information
Not 100% correct but some useful information
The Yanmar YS engines...
I ran out of fuel.
After that the engine was hard to start. It cranked over furiously, but took ages to fire up.
Bled the fuel 10 or more times.
Then I read in the above General Information site
“resetting the governor linkage at very frequent intervals. If the engine dies at low revs, and will not start, ”
So, I gave it a go and it solved the starting problem right away. I highly recommend this.
However the instructions in the manual are a little confusing. (page 38)
YSE YSB 8/12 HP manua l https://www.sailingthanksdad.com/documentation/Yanmar-YSE-YSBServiceManual.pdf
I have rewritten the process resetting the linkage and will add it as a POF here.
This requires limited tools and is (a very rare) 5 minute job.
All the best
gary
jiris
Member
I don't think it would be the linkage. This problem would cause the pump delivering no fuel - while the OP says fuel IS being delivered. If there is also air and compression, the only conclusion is the fuel is being injected at the wrong time.
garymalmgren
Active member
I don't think it would be the linkage. This problem would cause the pump delivering no fuel - while the OP says fuel IS being delivered. If there is also air and compression, the only conclusion is the fuel is being injected at the wrong time.
The linkage is the adjustment for injection timing.
gary
The linkage is the adjustment for injection timing.
gary
Bilgediver
Well-known member
Before cranking it is best to establish a fuel flow using the lift pump on the engine. Be methodical and work along the system establishing where the fuel has reached. You may have to rotate the engine to a best position to get the full stroke on the lift pump so it gives full delivery. The first thing to do is pump using the lift pump till you have fuel at the inlet connection of the high pressure fuel pump which you should slacken off. If there is a problem getting fuel to this point just using the lift pump then slightly pressurising the fuel tank using something like a dinghy pump can help I use the tank filler and a rag around the air hose is sufficient and there is enough airflow even if air is lost via the breather just pumping slowly with hands not feet. If doing this and you have a primary filter before the lift pump then ensure this is totally full by loosening the bleed screw on the top or the outlet connection long enough to get fuel flow without bubbles in fuel then tighten. now loosen the outlet on the lift pump till no bubbles. You should now be able to use the lift pump without air pressure on the tank so loosen the bleed screw on the fuel pump and pump lift pump till no bubbles of air at fuel pump. Tighten all and now loosen high pressure connection to injector and crank engine till no air bubbles in fuel at injector then tighten injector inlet. Crank engine with 3/4 throttle and should start.
If you cannot get fuel to injector after priming the HP fuel pump come back for the dodge for that but be sure to be able to tell us how far the fuel did get.
earlybird
Well-known member
Injection timing on these engines is set by shimming. I'd think that this is unlikely to need resetting unless someone has been fiddling. Injection makes an audible squeaking sound when the engine is cranked by hand with the decompressor lifted. If this can't be heard then there's probably still some air in the system. Only delve deeper if the squeak is audible and still no go.
Don't forget to bleed on full speed setting.
Don't forget to bleed on full speed setting.
garymalmgren
Active member
Re Bilgediver
.best to establish a fuel flow using the lift pump on the engine
pump using the lift pump till you have fuel at the inlet connection .
The YS series engines are gravity feed and do not have fuel supply pump (lift pump)
I think you are thinking of later model (GM) engines.
Re earlybird.
Injection timing on these engines is set by shimming.
I'm sorry to say that this is not so.
There is no shiming on this engine.
The fuel pump piston is run from a cam which gives the basic fuel injection timing and the linkages give the fine tuning of the timing.
I will post a link to the manual as a reference. (page 38)
YSE YSB 8/12 HP manualhttps://www.sailingthanksdad.com/documentation/Yanmar-YSE-YSBServiceManual.pdf
gary
.best to establish a fuel flow using the lift pump on the engine
pump using the lift pump till you have fuel at the inlet connection .
The YS series engines are gravity feed and do not have fuel supply pump (lift pump)
I think you are thinking of later model (GM) engines.
Re earlybird.
Injection timing on these engines is set by shimming.
I'm sorry to say that this is not so.
There is no shiming on this engine.
The fuel pump piston is run from a cam which gives the basic fuel injection timing and the linkages give the fine tuning of the timing.
I will post a link to the manual as a reference. (page 38)
YSE YSB 8/12 HP manualhttps://www.sailingthanksdad.com/documentation/Yanmar-YSE-YSBServiceManual.pdf
gary
CJU
Member
On some YS engines the return spill pipe from the injector goes back to the top of the engine fuel filter, not back to the tank. This can make bleeding the air out of the system a long process, as the air just keeps going round and round.
You also have to bleed up to the injector by slackening the union on the feed pipe until fuel comes out when the engine should fire. There should also be an audible click when the injector opens on the firing stroke.
You also have to bleed up to the injector by slackening the union on the feed pipe until fuel comes out when the engine should fire. There should also be an audible click when the injector opens on the firing stroke.
earlybird
Well-known member
Have a look at p39, para. 9.3.2 of your reference which explains how to add or remove timing adjustment plates under the pump mount. 0.1mm thickness = 2 deg. injection timing change.
Sounds like shimming to me.
jiris
Member
Yep. Thanks.
Bilgediver
Well-known member
I will post a link to the manual as a reference. (page 38)
YSE YSB 8/12 HP manualhttps://www.sailingthanksdad.com/documentation/Yanmar-YSE-YSBServiceManual.pdf
Wrong Manual. The OP told us it is a YSM-8 and this engine has a lift pump.
YSE YSB 8/12 HP manualhttps://www.sailingthanksdad.com/documentation/Yanmar-YSE-YSBServiceManual.pdf
Wrong Manual. The OP told us it is a YSM-8 and this engine has a lift pump.
paulg567
New member
Hi all
I have a YSM8 and wrote one of the original posts
The issue is very unlikely to be injection timing
The engine has indeed got a lift pump on the RHS of the engine.
If you have fully bled the system and it starts but only runs for a few minutes, it sounds like it may be some sort of fuel starvation.
This could either be caused by an airlock, filter blockage, an air leak in the system, or a defective lift pump
Check filters first, then the lift pump. Otherwise, are the seals on the primary and secondary filter bowls all good?
Cheers
I have a YSM8 and wrote one of the original posts
The issue is very unlikely to be injection timing
The engine has indeed got a lift pump on the RHS of the engine.
If you have fully bled the system and it starts but only runs for a few minutes, it sounds like it may be some sort of fuel starvation.
This could either be caused by an airlock, filter blockage, an air leak in the system, or a defective lift pump
Check filters first, then the lift pump. Otherwise, are the seals on the primary and secondary filter bowls all good?
Cheers
Bilgediver
Well-known member
One thing which might be worth checking is if the lift pump has an internal filter. Some do and these are usually identified because the cover is secured by a screw in the centre of the dome. The filter is a small plastic bucket element which is easily cleaned with a small brush. It is surprising how these can choke up with debris that has come through the primary filter causing the symptoms you describe.
alexey
New member
Today I have fixed the problem with my YSM8. The engine runs just fine now. It ran for about 30 minutes in total, including high RPM.
Thank you all for help! Your advice helped me get through. I can prepare the engine for winter now. It's getting colder each day here.
I believe I had an airlock. I couldn't get rid of it because of bleeding-then-trying-to-run sequence. Here is what I did many times over, and it didn't help me:
* bleed everything according to the manual, including high pressure side
* try to start the engine
* watch engine struggle for 10-40 seconds and stall
* repeat from the beginning
I suspect the engine was pushing the air bubble around through the fuel return pipe every time it stalled.
Here is what I did today, and it worked:
* bleed low pressure points, few rounds
* bleed everything, including high pressure side, few rounds
* try to start the engine
* yay!
During the process I couldn't see any bubbles, only pure fuel. Especially on the injection pump inlet bleeding bolt. On YSM8 this bolt does not have a proper bleeding through-hole, only a groove. I had to unscrew it quite a lot to get the fuel flow, compared to bleeding bolt on the secondary filter. The latter was very easy to start getting fuel out. I've noticed a peculiar thing while bleeding injection pump inlet. Fuel stream was uneven. For some time it was only a little fuel, but suddenly there was a bit more fuel coming out. (Air bubble?)
Tomorrow I'll try starting the engine again. If it does run, it will confirm that it was only an airlock. (And likely no air leak.)
By the way, before getting to this point I replaced:
Indeed YSM is horrible with air bleeding. I totally understand why people install priming bulb or electric pump. I've decided not to do it yet. But I may reconsider next season.
P.S. I can see some tiny amount of liquid underneath the engine. It was leaking the whole summer and it didn't seem to bring any troubles. I can't even tell if it's diesel or oil. I plan to find out where it comes from. There's a chance it's related to my air bleeding troubles.
[1]: I've replaced whole secondary filter, because I broke bleeding bolt thread on the filter cover. It's very important to be very gentle on bolts with plastic washers. It's enough to hand tight and then tiny snug with a wrench tiny (quarter turn or less). If it leaks you could always tighten it more (I never had to).
[2]: Here is my super simple primary filter. I'll probably put back my CAV296 next spring, to get water separation. This one doesn't do it:
FUEL FILTER UNIVERSAL (BETWEEN THE HOSES)
[3]: Some of the old washers were quite a mess. I'm very happy I replaced them.
Thank you all for help! Your advice helped me get through. I can prepare the engine for winter now. It's getting colder each day here.
I believe I had an airlock. I couldn't get rid of it because of bleeding-then-trying-to-run sequence. Here is what I did many times over, and it didn't help me:
* bleed everything according to the manual, including high pressure side
* try to start the engine
* watch engine struggle for 10-40 seconds and stall
* repeat from the beginning
I suspect the engine was pushing the air bubble around through the fuel return pipe every time it stalled.
Here is what I did today, and it worked:
* bleed low pressure points, few rounds
* bleed everything, including high pressure side, few rounds
* try to start the engine
* yay!
During the process I couldn't see any bubbles, only pure fuel. Especially on the injection pump inlet bleeding bolt. On YSM8 this bolt does not have a proper bleeding through-hole, only a groove. I had to unscrew it quite a lot to get the fuel flow, compared to bleeding bolt on the secondary filter. The latter was very easy to start getting fuel out. I've noticed a peculiar thing while bleeding injection pump inlet. Fuel stream was uneven. For some time it was only a little fuel, but suddenly there was a bit more fuel coming out. (Air bubble?)
Tomorrow I'll try starting the engine again. If it does run, it will confirm that it was only an airlock. (And likely no air leak.)
By the way, before getting to this point I replaced:
- whole secondary fuel filter assembly [1]
- whole primary filter assembly (replaced half-a-dozen-seals CAV296 with a super cheap and extremely simple inline filter) [2]
- all copper washers that I've touched during previous air bleeding frenzy [3]
- injection pump inlet bleeding bolt and its plastic washer
Indeed YSM is horrible with air bleeding. I totally understand why people install priming bulb or electric pump. I've decided not to do it yet. But I may reconsider next season.
P.S. I can see some tiny amount of liquid underneath the engine. It was leaking the whole summer and it didn't seem to bring any troubles. I can't even tell if it's diesel or oil. I plan to find out where it comes from. There's a chance it's related to my air bleeding troubles.
[1]: I've replaced whole secondary filter, because I broke bleeding bolt thread on the filter cover. It's very important to be very gentle on bolts with plastic washers. It's enough to hand tight and then tiny snug with a wrench tiny (quarter turn or less). If it leaks you could always tighten it more (I never had to).
[2]: Here is my super simple primary filter. I'll probably put back my CAV296 next spring, to get water separation. This one doesn't do it:
FUEL FILTER UNIVERSAL (BETWEEN THE HOSES)
[3]: Some of the old washers were quite a mess. I'm very happy I replaced them.