yanmar 2GM wont fire up unless governor at/very near WOT?

[vas]

evening all,

new issue with my generator 2GMF...
Used to be able to start it at say 1500-1800rpm from cold (so less than half throttle).
over the last month it developed a habit of catching, running for a few secs and dying.
Can do that half a dozen times unless I pull up the governor to almost full and crank for 7-8secs where it catches and fires up.
Temps at the e/r are 12-15 so not cold (used to start fine with 5-7C in the e/r two months ago!

Have done half the service for it (oil/oil filter) and haven't done the yanmar fuel filter yet. about to do it during the week.
I don't believe I have diesel bug (main engine filters are clean) but we shall see once I replace it.
I have removed and blanked the mech lift pump and replaced it with an el.one which seems to be working fine and pumps lots of diesel.

any ideas I may be missing?

V.

 

[ChromeDome]

Not other than it is common, esp. when cold as they have no cold-start system.
The high pressure pump on these is dead simple so not much to go wrong there.

I've fitted a glow plug to the airfilter pot for a friend and it helps (colder that yours, in the Baltics), but it needs at least 2 minutes pre heating and half throttle to start.
Before that he used to run a heat fan (1000w/240v), blowing directly on the airfilter pot & intake area for 10 minutes which made it start at idle every time.

 

[DownWest]

Easy start...

 

[vas]

thanks,

what confuses me is that within 2months and as the weather is getting warming (in the med) it started becoming more difficult to start, that's why I'm wondering if I'm missing something.

cheers

V.

 

[DownWest]

thanks,

what confuses me is that within 2months and as the weather is getting warming (in the med) it started becoming more difficult to start, that's why I'm wondering if I'm missing something.

cheers

V.

Sorry about the 'Easy Start' post. It does sound a bit odd.

 

[vas]

actually coming to think of it, maybe the starter is becoming weaker? or the bat is not full (although I have it on a trickle charger permanently)
cranking doesn't manage more than circa 650rpm, I think I was getting more before.
so easy and clean options first, will get a proper victron charger on the battery for a day and will take off the starter to check brushes...
then do smelly diesel at the w/e ...

V.

 

[vas]

well had time this morning to have a better look. Replaced the yanmar diesel filter, was v.clean changed 3yrs ago and circa 60h.
Was a b1tch to start, was hunting, stopping, ended up full wot to fire up, then it would drop revs and die after 10secs. Generally a mess.
Have an electric lift pump, so bleeding the filter was quick. then bled the lines again and again,
Opened the two injector pipe nuts (ok, one by one) while running, both affected and drop rpm/died if I wasn't fast, so no a cyl/injector problem
Then had a look at the air filter, was a bit of a mess with a bit of oil (coming from the inlet?)
Filter off, after a few more goes it fired up and kept going at 3k rpm (2-pole generator) with no issues.
Even stopped it and started again an hour later and it worked (fired on second attempt)

Will have another look in the evening, bet it wont fire straight ahead.
Wondering if there's some blockage on the diesel line bringing fuel from the tank. Pipe is circa 4m long.
I have a spare tank of diesel onboard will try with two short lines and see if it is any better.
Else I'm running out of ideas.

Starter is strong, no issues, battery the same checked with a el. tester, also checked cables for voltage drop and connections, all fine.
So seems that it's fuel related (or was the air filter to blame but it's too good to be true)

V.

 

[Alex_Blackwood]

well had time this morning to have a better look. Replaced the yanmar diesel filter, was v.clean changed 3yrs ago and circa 60h.
Was a b1tch to start, was hunting, stopping, ended up full wot to fire up, then it would drop revs and die after 10secs. Generally a mess.
Have an electric lift pump, so bleeding the filter was quick. then bled the lines again and again,
Opened the two injector pipe nuts (ok, one by one) while running, both affected and drop rpm/died if I wasn't fast, so no a cyl/injector problem
Then had a look at the air filter, was a bit of a mess with a bit of oil (coming from the inlet?)
Filter off, after a few more goes it fired up and kept going at 3k rpm (2-pole generator) with no issues.
Even stopped it and started again an hour later and it worked (fired on second attempt)

Will have another look in the evening, bet it wont fire straight ahead.
Wondering if there's some blockage on the diesel line bringing fuel from the tank. Pipe is circa 4m long.
I have a spare tank of diesel onboard will try with two short lines and see if it is any better.
Else I'm running out of ideas.

Starter is strong, no issues, battery the same checked with a el. tester, also checked cables for voltage drop and connections, all fine.
So seems that it's fuel related (or was the air filter to blame but it's too good to be true)

V.

Air filter. Wouldn't take bets on it not being that!

 

[Bilgediver]

thanks,

what confuses me is that within 2months and as the weather is getting warming (in the med) it started becoming more difficult to start, that's why I'm wondering if I'm missing something.

cheers

V.

Try bleeding to the injector and see if air comes out. The fact that you have to race the engne as soon as it starts suggest there may be air in the fuel which clears once flow is established. It might be worth checking the o ring seals on the fuel filters . If you have a CAV filter has the O ring on the centre bolt been replaced in living memory

 

[garymalmgren]

RE': Starter is strong, no issues, battery the same checked with a el. tester, also checked cables for voltage drop and connections, all fine.
So seems that it's fuel related (or was the air filter to blame but it's too good to be true)

It IS FUEL related.
1. Not enough fuel = blocked filter, blocked fuel pick up tube, blocked fuel cock on tank. Check and clean.
2. Bad fuel = Contaminated with water, rust flakes or other. Change filters again, Use new fuel.
3. Air lock. You have bled the lines and that seems to have been eliminated, but do it again just to be on the safe side.

RE: was the air filter to blame
The air filter is usually a foam material the deteriorates and is sucked into the engine. It is combusted there and excreted.
One of the main functions of the air cleaner (besides cleaning the intake air) is to muffle the sound of the air being sucked into the engine , which can be quite loud. It should not make any real difference to the start up of the engine.

gary

 

[vas]

thanks for the comments,

CAV is on a drawer in the garage, not going to use it again, great pain with the o-rings.
Did bleed the filter top, high pressure pump in, and injectors pipe in.
Had to tighten the yanmar engine mount filter a couple of times to stop a tiny leak. Bled again afterwards.

Now fuelwise, tank and fuel is fine, both main engines run with no issues. However, thinking about it, the main tanks (1200lt now just under 1/3) feed into a 5lt daytank and two main engine pickups are on top of that, generator is on the side and fairly low. So next step is to work the stopcock (did it once today to check the feel...), undo the pipe, and collect a couple of litres from the juice in a can for inspection. Haven't done that for a few years now.
I'll also bleed the lot again just in case.

Foam filter is in good nick, but feels stuffed with soot and a bit of oil, so not sure how easy is for the air to go through. Will try to clean it or get a new one.
should have some news later on today else Tue

cheers
V

 

[Alex_Blackwood]

RE': Starter is strong, no issues, battery the same checked with a el. tester, also checked cables for voltage drop and connections, all fine.
So seems that it's fuel related (or was the air filter to blame but it's too good to be true)

It IS FUEL related.
1. Not enough fuel = blocked filter, blocked fuel pick up tube, blocked fuel cock on tank. Check and clean.
2. Bad fuel = Contaminated with water, rust flakes or other. Change filters again, Use new fuel.
3. Air lock. You have bled the lines and that seems to have been eliminated, but do it again just to be on the safe side.

RE: was the air filter to blame
The air filter is usually a foam material the deteriorates and is sucked into the engine. It is combusted there and excreted.
One of the main functions of the air cleaner (besides cleaning the intake air) is to muffle the sound of the air being sucked into the engine , which can be quite loud. It should not make any real difference to the start up of the engine.

gary

He says that it ran OK when the air filter was removed. At least that is how I read it!

 

[vas]

He says that it ran OK when the air filter was removed. At least that is how I read it!

indeed, that's what I said, but was it due to the removal of the filter, or due to all the tinkering with bleeding and messing about I did just before?
that's why I want to try firing it up from stone cold later on this evening and see what I get. If it starts, I'll get a new air filter and consider it sorted.
If not, I'll keep on getting my hands dirty with diesel till sorted...

V.

 

[DownWest]

thanks for the comments,

Had to tighten the yanmar engine mount filter a couple of times to stop a tiny leak. Bled again afterwards.

cheers
V

If the Yanmar filter is an O ring seal, it should seal with gentle pressure and a bit more to make sure it doesn't come loose. Having to tighten it twice sounds like there might be an issue with the ring or surfaces.
Long time ago, had this with a Petter genset. Of course the fault was ni on impossible to see without mirrors and torches, so was missed for a bit.

But, normally with an electric pump, you don't have issues with low pressure air leaks, more fuel seeping out of any gap. Unless it is before the pump and it has to lift from the tank level.

 

[vas]

well, the new o-ring I used was sealed in the MANN replacement filter box, fitted perfectly and the two mating surfaces are nice and clean anyway (have stripped the bleeding hole years ago and had to take it to a machinist to fix and had a check on the surfaces there).
I think it was mainly the fact that the yanmar one needs some care in tightening it and was slippery with diesel, so was taking it easy.
true el.pump is helpful, as is the pressure sender I fitted on top of the fuel filter which registers +0.5bar constantly, so no leak up to the high pressure pump even after a week off.

V.

 

[mil1194]

This all sounds very very similar to my Westerbeke issues and I’m convinced it’s diesel supply related. I need to setup a separate supply (from a height advantage) to check first of all.

 

[vas]

sorry for the late update, engine didn't start on 3 8sec cranking sessions.
next step is disconnecting the 4m supply line, check/blow it, see there's no blockage on the supply stopcock and go from there (short pipe to an extra canister and bleed/start from there)
back home tomorrow, so if the weather is fine, I'll do that then

V

 

[Biggles Wader]

Have you definitely excluded a blocked air filter as the problem? If so it sounds like the problem I had with fuel supply from the tank pick up which was becoming clogged with crap. No sign of rubbish in the fuel filters but the engine was hunting and stalling and ultimately wouldnt run. I cleaned out the tank and put in new fuel lines which sorted it.

 

[vas]

yes, haven't refitted the housing/filter combo yet.
Well, mine will struggle to start, once it's up and running wont fail and wont stop by itself.
I'll do a v.long session of bleeding first tomorrow and then start messing with the pipework I think.

V.

 

[roaringgirl]

Leave it overnight to cool, take a fresh short fuel line and run it to a clean jerrycan of fuel and try starting it.