yanmar 1gm10 a pig to start!

[toothless]

Since owning my contessa 26 the 1gm10 has been a sod to start when I first get aboard, irrespective of the weather / temperature. I always turn her over with the decompressor lever up to get her spinning and oil pumping, then drop it after a few seconds. If shes warm, she pops right into life, but if cold you are cranking endlessly with the odd splutter and cough once she is about to take. Once she starts, she runs right as rain, no smoke etc. I have had the engine start backwards on one or two occassions which is alarming as the cabin fills with fumes but I always kill it straight away when that happens, and it hasn't happened in a few years anyway.

Things I have considered so far:
New air filter
New fuel filters
Checked the tank etc for goop. There wasnt any. Treated with diesel bug treatment anyway.
Electric clicky clacky fuel pump (to make priming easier)
Primed the fuel system (many times)
Checked the exhaust (but not before I decided to buy a stainless elbow online - on going to fit this I found the previous owner had already done it, Doh! At least I have a spare) - no particular coking and not blocked.
Tried to turn her over by hand as a compression test - absolute bastard to do it, but with decompressor activated is easy enough, so I am confident there is compression.
New water pump
Tried every throttle position
Of note I only open the seacock when the engine catches so I dont flood it.

I am a bit at a loss. I have put up with it for a few years but finally have had enough. Anyone got any other suggestions?

 

[Boater Sam]

Get a gas blowlamp going down the inlet as you start. There is no substitute for a bit of heat, better than all the Start Ya Bastard.

 

[Stemar]

I'm no expert, but you seem to have covered most of the likely stuff. One though, though, Do the injector and/or injector pump need a service? If the pressure's a bit low, or the spray a bit coarse, I could see that causing poor starting from cold. Alternatively, I had a VP2003, which is an engine that's a pig to start from cold if you don't use the correct technique, and a lot of people didn't understand it.

PS: Am I right in thinking that the 1GM10 doesn't have a heater plug? If it does, that would be my first target.

 

[toothless]

Correct, no heater plug. I probably do need to look at the injector and pump next - boo!

 

[Stemar]

Just in case you aren't aware of it, I understand that the 1GM10 has an oil pipe below the raw water pump, in just the right place for drips from a leaky pump to land on it. It's made of mild steel, so drips will corrode it far quicker than you'd want. Just something to keep an eye on.

Someone who knows what they're talking about will be along in a minute to confirm or deny ...

 

[Refueler]

Pal of mine had exactly same problem ... turned out to be the little fuel pump regulator ... a right pig to get it right if you DIY service it !!

I have no idea what its real name is ... all I know is that he showed it to me and was not talking in sweet loving terms !!

Just remembered - couple years back - I asked on here if anyone had one to sell !!

 

[toothless]

Just in case you aren't aware of it, I understand that the 1GM10 has an oil pipe below the raw water pump, in just the right place for drips from a leaky pump to land on it. It's made of mild steel, so drips will corrode it far quicker than you'd want. Just something to keep an eye on.

Someone who knows what they're talking about will be along in a minute to confirm or deny ...

Yup spot on - my oil pipes are slathered in paint to prevent that, and I changed the water pump due to it starting to look a bit leaky. I keep a close eye!

Pal of mine had exactly same problem ... turned out to be the little fuel pump regulator ... a right pig to get it right if you DIY service it !!

I have no idea what its real name is ... all I know is that he showed it to me and was not talking in sweet loving terms !!

Just remembered - couple years back - I asked on here if anyone had one to sell !!

interesting. I will have look at the service manual and see if i can figure that out. thanks

 

[Refueler]

Yup spot on - my oil pipes are slathered in paint to prevent that, and I changed the water pump due to it starting to look a bit leaky. I keep a close eye!

interesting. I will have look at the service manual and see if i can figure that out. thanks

Page 104 of the full service manual ..... no idea if your problem is same .. but I know he gave up with it and fitted a replacement unit ..

Interesting - he never used the decomp lever on his ... and I've never used on my 2GM either .. I( assumed the decomp was more for if using the starting handle ??

 

[lexi]

Had the same issue. You can do all the in situ stuff first. Mine was starting backward too. I rebuilt the engine to a lengthy standard. Piston rings were worn. You may be lucky and have worn valves on the head only, or get away with injector service. Once you open them up you find all sorts of wear though. A shot to nothing could be to take the head off and do the injector. Instead of possibly wasting £90 on the Yanmar head gasket, you can get a good Recmar one for £22. Hard to do a compression check on these engines without proper gauge.

 

[pete]

I had the same problem but only on the first start of the day. The engine became very hard to start with a long crank being required which was unusual for this engine. We tried all the obvious things when we went to the boat each weekend (for over about 6 weekends). When started the engine ran fine and would restart immediately. As a pure fluke with the engine turned off I put my finger in the oil filler hole in the front of the engine and poked around under the injection pump, I felt a spring suddenly return as I touched it, I guess it was connecting the injection pump to the engines governor which increases diesel just for starting. The engine started well after that and was back to normal. The fault never reappeared all the time I had the boat.
I know your problem could be caused by many things but it's worth a look and costs you nothing.

 

[toothless]

I had the same problem but only on the first start of the day. The engine became very hard to start with a long crank being required which was unusual for this engine. We tried all the obvious things when we went to the boat each weekend (for over about 6 weekends). When started the engine ran fine and would restart immediately. As a pure fluke with the engine turned off I put my finger in the oil filler hole in the front of the engine and poked around under the injection pump, I felt a spring suddenly return as I touched it, I guess it was connecting the injection pump to the engines governor which increases diesel just for starting. The engine started well after that and was back to normal. The fault never reappeared all the time I had the boat.
I know your problem could be caused by many things but it's worth a look and costs you nothing.

That's the sort of fix I'm hoping for! Will have a poke around. I'm increasingly resigned to taking the head off, but we will see.

 

[dukeofted]

Definitely get the injector serviced. Mine was exactly the same as yours and an injector service transformed the cold starting.

 

[garymalmgren]

RE; Pete's post.
I put my finger in the oil filler hole in the front of the engine and poked around under the injection pump, I felt a spring suddenly return as I touched it,

That is very interesting as that spring in the parts manual is identified as SPRING, STARTING.

 

[lexi]

That is the rack setting in the oil filler hole. Usually only gets out of position when it has been assembled wrong. worth a look as it may have jumped. Having had every bit of that in my hand, I still could not figure how it gave extra fuel when starting as there is no throttle to speak of. I replaced Governor springs with new. I start my 1gm 10 with no throttle, and only use decompressor lever to spin up oil pressure.

 

[LiftyK]

My 1GM10 normally starts easily with the throttle at idle position. After an alternator problem, long story, I had a non-Yanmar alternator fitted. With the new alternator in place, the engine really struggled to start and sometimes ran backwards, just like yours. If I could use the throttle to coax it through the stuttering phase, it was then fine. The problem was that the third-party alternator had a standard sized pulley. The 1GM10 is of such low power that when cold starting it needs an easier to spin pulley on the alternator, otherwise there isn't enough power to get going. I think this means that the Yanmar supplier alternator has a larger pulley just for the 1GM10 that makes it easier for the engine to turn over when cold.

I had the original Yanmar alternator with 1GM10-specific pulley repaired. On fitting it, the engine instantly became easy to start again. One possible reason for your starting difficulties, if the engine has always behaved this way or if you changed alternator.

 

[lexi]

Before you remove the head, try adjusting the valve clearances. Tight tappets or valve recession can alter the clearances. It is a free shot to nothing.

 

[andsarkit]

My 1GM10 normally starts easily with the throttle at idle position. After an alternator problem, long story, I had a non-Yanmar alternator fitted. With the new alternator in place, the engine really struggled to start and sometimes ran backwards, just like yours. If I could use the throttle to coax it through the stuttering phase, it was then fine. The problem was that the third-party alternator had a standard sized pulley. The 1GM10 is of such low power that when cold starting it needs an easier to spin pulley on the alternator, otherwise there isn't enough power to get going. I think this means that the Yanmar supplier alternator has a larger pulley just for the 1GM10 that makes it easier for the engine to turn over when cold.

I had the original Yanmar alternator with 1GM10-specific pulley repaired. On fitting it, the engine instantly became easy to start again. One possible reason for your starting difficulties, if the engine has always behaved this way or if you changed alternator.

This is easy to check if you just remove the alternator belt and see if this improves starting.
Some details on the different pulley sizes:
There are two sizes of belt used on the 1GM10. 29" and 31".
Yanmar part number: 105582-77790E for later 1GM10 (After serial no. E03690)
The Earlier engines (Up to serial no. E03690) use the 29" belt part number: 128170-77350)

 

[toothless]

I pulled the injector today and found this so I'll get that looked at and see what's what. No joy poking around the governor so sadly not that simple a fix. I'll try the valve clearance next if the injector doesn't do it

 

[Pye_End]

Battery ok? Only takes a small, barely noticable drop off in grunt for it to be a difficult starter.

 

[oldbloke]

Maybe ttg bypassing all your wiring and connectors with some nice fat jump leads and see what happens. On my old boat most problems ended up being due to crappy electrics