Perkins 4108 injectors

[NCSailor]

When do you have injectors serviced?

[HappyMdRSailor]

Originally Posted by NCSailor

When do you have injectors serviced?

When the smoke signals say so...

[model 10]

To bad smoke is not the only thing that can go wrong. Sticking would worry me more. I don't need another loud knocking noise coming from my engine.
I would have them serviced if the pump was out for repair.

[a64pilot]

The knock a cold engine makes, but doesn't go away is one very good indicator, however I would run some techron or auto tranny fluid or seafoam through it first to see if the knock goes away, dirty (varnished) injectors will have their spray pattern altered and this will cause the knock.
Rough idle, more smoke than normal or just a change in the way it runs is enough to try the cleaner and if that doesn't work a service may e in order.

[Arthur Garfield]

Above reasons-I.E.,smoke(unburnt fuel),rough running,excessive fuel consumption...may indicate injector problem.Most often this ocurrs from sticking injector(s) from old fuel. Often an injector cleaner additive will turn the trick running with elevated RPMs to clear.Upon little or no effect of cleaning additive the next step should be injector nozzle tip testing.Many times the nozzel tip(s) will cause uneven and or abnormal spray pattern that will cause the above inefficencies.A change of nozzel tips usually will remedy without expense of an injector change.

[NCSailor]

I question the injectors because my Perkins is 1979 vintage and never serviced. I do see a little smoke but not much different than in the past. What has change in after hours of motoring I get black stain at the waterline on the transom. Not a problem to clean but this is new over the last year.

[Cheechako]

if the engine runs good, leave it. If not service them. JMHO

[CSY Man]

The book says every 400 hours...

[NCSailor]

Really - every 400 hrs you pull the fuel injectors an shave them serviced?

[CSY Man]

Yup, I did, but sometimes stretched it to 500 hrs.
These are the old type injectors that needed more frequent servicing, newer ones
Can go more than double that.


Sent from my iPad using Cruisers Sailing Forum

[NCSailor]

Thanks CSY Man

[model 10]

What do the ovhl shops actually do? The standard invoice says"clean and pressure test". Can we actually do the clean part?

[CSY Man]

New parts?
I have seen one of my injectors tested before overhaul, the fuel was only dribbling out.
After overhaul a proper spray pattern was seen.
Not sure what they do, but It works.


Sent from my iPad using Cruisers Sailing Forum

[oldcal46skipper]

I test, clean, rebuild and calibrate about 100 or so 4.108 injectors each year.
Ma Perkins says do this each 400 hours, but if you keep clean water free fuel you can stretch it to 1,000 hours or until any of the symptoms listed above appear.

When someone brings me injectors to rebuild, I always ask them to watch my prelimanary test as it tells them a lot. Dirty fuel or water in the fuel corrodes the tips fast and corrupts the fuel pattern. Ever wonder why the Brits call them "Atomizers"?

Extra fuel consumption can pay for rebuilds fast. If you are ever down on Bayou Chico, come by and I will show you what a bad pattern looks like.

Tom

[NCSailor]

Thanks Tom. Sounds like I should get a Mechanic to look at mine. Certainly over 1K hours. I have owned this boat since the late 80's.

Any recommendation in the New Bern, NC area?