Yanmar Injectors

[SteveIOW]

I have decided to have the injectors on my Yanmar 2GM20 serviced. Can some one please advise what seals need to be replaced and which can be re-used:
a) My manual doesn't seem to show a washer under the injector where it screws into the cylinder head though I believe there is a copper washer there (Renew I presume).
b) There appears to be Two Sealing Washers for each injector at the fuel return pipe connection (re-use?).
c) I won't be dismantling the injectors myself but should the Packing between the Nozzle Spring Nut and the Nozzle Holder Body be renewed?

 

[charles_reed]

If you anneal the copper washers they are usually re-usable.

Servicing on such simple injectors is no mor than checking pressure and pattern - best done by a qualified diesel injection shop. Remarkably few and far between.

 

[richardabeattie]

I've never done that on my 2GM20 so you've got me worried. Why have you decided to do it?

 

[NorthUp]

If you anneal the copper washers they are usually re-usable.

Servicing on such simple injectors is no mor than checking pressure and pattern - best done by a qualified diesel injection shop. Remarkably few and far between.

You have described testing an injector. Servicing is a bit more involved.

 

[nemodreams]

The copper washer under the injector is a recent addition - after the switch to non asbestos heatproof washers. Formerly - the injector sat onto a heatproof washer. Now it sits on a thin copper shim on top of a heatproof washer.

If just servicing removing the injector I would suggest leaving the entire base assembly as is. Its very difficult to prise out the washer - as it the full size of the bore - and is very thin.
The precon chamber has hole in the middle and any bits go straight down into the combustion chamber ! - which has top clearance of 0.6mm !

If wanting to change the seals under the injector - its easer to pull up the top half of the precon chamber - using some sort of hook through the hole,
One can then remove the copper washer, prise out the heatprof washer from its groove ( difficult even when on the bench ) - and maybe ! manage to lift out the copper washer between the two halves of the chamber.
I have done it and it was far from easy. Much easier with the head off !

Here is a pic of a stripped down yanmar pre con chamber assembly - ie this is what the injector bolts down on top of.
Left to right - copper shim ( injector base sits on this ) - heatproof washer - top half precon chamber - copper washer - lower half chamber - base washer.

The brass bar 'tool' is how i originally got the top half the precon chamber out ( before I had the head off ) Its fashioned to go through the hole - then a small wedge is pushed into the split - then the unit can be pulled up the injector bore hole.

Have fun !

 

[Topcat47]

I don't know anywhere on the island who services them, but I use Panda in Fareham. I always do pumps and injectors together. They should be paired.

 

[classic jenny]

DTM in Bristol are excellent and will happily test your injectors and make any repairs have know quite a few people use them for boats and road going vehicles all with positive outcomes

 

[[164147]]

I had mine done by Dave Crawford Marine for a 4LH-STE. They clean them ultrasonically before testing and then replace injector heads as necessary or the whole unit if required. Something like £45 an injector + any replacement cost.

 

[SteveIOW]

Thank you for the advice (especially from "nemodreams"). It sounds as though removing the copper washer & heatproof washer under the injector is difficult unless you also remove the pre combustion chamber with a purpose made tool. I have no particular wish to remove the pre combustion chamber so am temped to remove and replace the injector (after servicing) on the existing washers. How big is the risk of not achieving an adequate seal on the old washers? I'm sure others must of done the same and got away with it

 

[sailorman]

why have you decided to have the injectors serviced

 

[[164147]]

Why not just buy new washers?

 

[richardabeattie]

why have you decided to have the injectors serviced

That's what I asked but no answer!

 

[SteveIOW]

Why not just buy new washers?

The problem is removing the old washers (see nemodreams post No 5 above). Obtaining / fitting new washers is the easy bit!

 

[nemodreams]

Yes - the copper shim welds itself to the heatproof below. The heatproof is welded to the top of the upper injection half - not helped by the fact its in a recess groove !
However - the injector will lift cleanly off the copper shim. If using the same injector I would leave the washers as is. Maybe a new injector might be a different issue.
The injector base forms the circular ring shown on the copper shim. A new one is flat.
From experience - if wanting to change these seals - it probably quicker to take the head off !

 

[SteveIOW]

yes - the copper shim welds itself to the heatproof below. The heatproof is welded to the top of the upper injection half - not helped by the fact its in a recess groove !
However - the injector will lift cleanly off the copper shim. If using the same injector i would leave the washers as is. Maybe a new injector might be a different issue.
The injector base forms the circular ring shown on the copper shim. A new one is flat.
From experience - if wanting to change these seals - it probably quicker to take the head off !

thank you nemodreams for your advice and thank you for answering my specific queries and not going off at a tangent.

 

[sailorman]

That's what I asked but no answer!

And still no reply.
I had a car with 230k on the clock with no service to the injectors

 

[Stats007]

Cars don't tend to suffer from diesel bug. I had mine cleaned as fuel efficiency was below par at 750 hours - made a huge difference as one injector was out of spec due to fouling.

 

[SteveIOW]

For those that have asked why I'm removing injectors for servicing here goes:-

Engine exhaust has been smokey (lightish grey) for last couple of months. No engine oil being used and exhaust smells of diesel (noticeable when motoring downwind).

Dried out on slip. Cleaned fouling from prop & hull in case engine was being overloaded. Boat went a bit faster but no change to smoking exhaust.

Intake air filter/silencer is new & clean.

Checked / reset valve clearances.

Compression good.

Exhaust elbow and first section of exhaust hose renewed a year ago. Plenty of cooling water coming though.

Running out of things to check so thought injectors would be next on the diminishing list. They haven't been out for 15 years.

Haven't checked the return hose from injectors to tank yet but can't see how that would be blocked.

Any other suggestions?

 

[sailorman]

For those that have asked why I'm removing injectors for servicing here goes:-

Engine exhaust has been smokey (lightish grey) for last couple of months. No engine oil being used and exhaust smells of diesel (noticeable when motoring downwind).

Dried out on slip. Cleaned fouling from prop & hull in case engine was being overloaded. Boat went a bit faster but no change to smoking exhaust.

Intake air filter/silencer is new & clean.

Checked / reset valve clearances.

Compression good.

Exhaust elbow and first section of exhaust hose renewed a year ago. Plenty of cooling water coming though.

Running out of things to check so thought injectors would be next on the diminishing list. They haven't been out for 15 years.

Haven't checked the return hose from injectors to tank yet but can't see how that would be blocked.

Any other suggestions?

how long have you owned her
does the engine attain max rpm underway
is she over propped

 

[SteveIOW]

how long have you owned her
does the engine attain max rpm underway
is she over propped

Have owned same boat for past 29 years. Current Yanmar 2GM20 fitted by myself with current prop 23 years ago. No problems with smoke, prop size/pitch or revs for previous 22 years.