Rebuild Yanmar Injectors??

[ggray]

Is it economic to rebuild worn injectors from a 3GM30?

[a64pilot]

Of course.
You have a diesel injection shop do it. I had all four of my tips replaced on my 4JHE’s. Two were bad, but I wanted all four changed.
I believe even if you buy new ones, they have to be shimmed for that specific installation. One injector model may be used in several different engines.

[NoTies]

With the modern machining methods and tolerances it is usually possible to replace nozzles yourself in a clean environment without the need to shim them. I have a test rig but on every modern injector I find that after straight nozzle replacement the pressures are always within spec without needing to re-shim.

[Cheechako]

It depends on the cost from your source. I have had some cases where new injectors were cheap. But it's been several years.

[model 10]

You also have the choice of getting exchange injectors. The bigger shops don't bother rebuilding your injectors, they just exchange them from their stock of re-built injectors. It's often a better way to go. They usually use new parts to avoid any warranty problems.

[Wotname]

All good advice ^^.

Do you know for sure they are worn? If so, I would be inclined to buy new nozzles etc, rebuild them at home, try them on the engine (unfitted, just connected to the IP) to confirm spray pattern etc and then have them pop tested at your friendly injector shop.

[RaymondR]

Originally Posted by Wotname

All good advice ^^.

Do you know for sure they are worn? If so, I would be inclined to buy new nozzles etc, rebuild them at home, try them on the engine (unfitted, just connected to the IP) to confirm spray pattern etc and then have them pop tested at your friendly injector shop.

Did it a couple of times on my 3GM30, found there was enough give in the spring on the plunger that the new nozzles "broke" at approximately the same pressure as the old.

[ggray]

Thanks to all of you.

[Larry Florida]

How can one tell if injectors are worn?

[Cheechako]

Originally Posted by Larry Florida

How can one tell if injectors are worn?

Well, rough running is one sign, raw fuel out the exhaust shown on the water another. It's what a shop does when making them right again, they clean and check to make sure the nozzle is atomizing the fuel, not just spraying it, or worse making a stream of fuel.

[Compass790]

Originally Posted by Larry Florida

How can one tell if injectors are worn?

Its easy to check the spray pattern if your workshop manual tells you what the pattern is supposed to be. Also they shouldnt drip when coming up to opening pressure but you need a pop-tester for that. A diesel shop shouldnt charge much to test them. Its a 5 min job

[a64pilot]

Originally Posted by Larry Florida

How can one tell if injectors are worn?

It usually comes on so progressively you really can’t. And more often they are just dirty, but it’s a carbon deposit you can’t really clean off very well with a fuel additive.
It can manifest itself in hard starting, a knock when idling that sounds a lot like a cold engine does, being smoky when running, slight power loss most likely unnoticed as it comes so slowly, and slight fuel consumption increase.
It’s just too easy to have them cleaned, adjusted if necessary and tested. I feel sure my total bill for having all four tips replaced and cleaned, tested etc was less than $200, it may have been much less, but it’s not a big bill. Been much less if I didn’t have all four tips replaced, but mine were 27 yrs old, very low hours, but time does matter.
Bad injectors can over time cause damage to an engine, there is a real reason to get them cleaned and tested.
In my opinion it requires equipment that it’s not logical to have on a cruising boat to DIY, and too important for home brew hit them with a hammer type of tests, in my opinion.

It’s just the best way to ensure as smooth and quiet a running engine as possible.

[Larry Florida]

Thanks for the replies. Great info. My 2 cyl Westerbe is 1984. Not exhibiting any problems in this regard but may do as preventive maint as time allows. Will depend on how hard to remove and replace and turnaround time for rebuild.

[Compass790]

Originally Posted by Larry Florida

Thanks for the replies. Great info. My 2 cyl Westerbe is 1984. Not exhibiting any problems in this regard but may do as preventive maint as time allows. Will depend on how hard to remove and replace and turnaround time for rebuild.

The other thing I forgot to say is look on youtube. You may find something on there that helps

[Badsanta]

Originally Posted by Compass790

The other thing I forgot to say is look on youtube. You may find something on there that helps

I had all of mine rebult for the price of one new one.
My mechanic friend told me that for an older motor he felt it was better to have injectors rebult as opposed to getting a new one that was sitting on a shelf some where for 20 years.