Perkins 4108 Starting Problem

[avazquez]

My Perkins 4108 used to start normally. At some point I would run the engine but when returning to neutral I noticed that the rpm would be higher than normal for neutral (900 rpm intead of 700). I adjusted the idle back to 700-750 and next time I used it it did it again. Now the engine wont start inmediately unless I give it some fuel in neutral, it starts rough, I then have to warm it up, and it works fine. It seems like I have adjusted the idle to low for it to start but if I increase the idle then after runing the engine it goes back to the 900-950 idle.

Any suggestions?????

[CSY Man]

Have (had) the same problem on my 4-108.
Had a mech look at it and he said no problem really.
Adjust the idle to about 650 when warm, then it will need a little
fuel (throttle) when starting cold.

It could be some wear from the high-pressure pump, but everything
still runs good and strong so I ain't worrying about it.

Better to have a slow idle when warm, instead of a high idle that will
"clonk" the transmission when ya put it in gear.

With the idle adjusted low, my engine will still start when cold, but reluctantly and it takes a few more seconds spinning the starter.
(New starter, new batteries, no problem in that area)

Perhaps Never Monday or other diesel experts can add to the above..?

[donradcliffe]

My 4108 had the same issue after the injector pump was rebuilt in Australia. Like CSYman, I ended up setting the idle properly for a warm engine and gave it some throttle for a few minutes when starting cold. You could probably make it work better if you have the injector pump rebuilt, but I decided it wasn't worth the bother.

[Alan Wheeler]

The problem is common in most all Deisels that do not use cold starting aids. Several factors are at play, such as engine cylinder temp, fuel pump temp, fuel temp and oil temp. All conspire to keep the engien running slower than normal and once the engine gets warm enough, the revs start to pick up on them. As suggested, the best adive is to set the idle RPM correctly when the engine is hot. When you start, you have to give just a little throttle. Once the RPM starts to increase, then you back the throttle to normal idle position.

[S/V Antares]

Along with what alan said it Sounds like one or two of your injectors is loosing pressure between starts. It makes it hard to start untill the pressure in the line is built back up. Pop test the injectors and you will know.

Perkins had an option of an intake air heater for cold start but it did not do much.

Will

[avazquez]

Mine has the cold starting device disconnected. I have no idea where the cables go.

[CSY Man]

I have had my injectors rebuilt every 400 to 500 hours so that should not be the problem..That being said, it "seems" to start and run better with the newly overhauled injectors..(Atomizer for ya Aussies and Kiwis probably..? )

Last time I had 'em re-built I requested to stay in the shop and watch them test the injectors before and after the process..Quite a difference in spray pattern: Before they were worked on, the fuel only dribbled out, after, it was a fine spray or mist that came out.

As for cold starts: My boat has always lived in the tropics so no cold start devices was needed..Not in the future either: I will never sail or motor North of 26N..

One thing I noticed over the last 9 years with the P 4-108 it that the nuts holding the injectors in place can loosen up over time and that could perhaps cause a small loss of compression and some shatter.
Torque 'em down to 15lbs or so before you do anything else.

The injectors are old style and needs more TLC than modern ones, hence the factory request they be overhauled every 400 hours.
Some guys have gone over 1000 hrs without any appearant problems, but I would think the engine would run less efficient and be harder to start with "stale" injectors.

I am hoping my injector pump will last many more moons, but it is getting up there in age and I have been quoted $1,500.00 US for an overhaul.

Is this excessive....?

(Yeah I could shop around, but would not perhaps choose the cheapest shop either...Bad economy if they screw it up)

[Pblais]

I am hoping my injector pump will last many more moons, but it is getting up there in age and I have been quoted $1,500.00 US for an overhaul.

Is this excessive....?

Depends. If you pull the engine and deliver it to the shop and put it back in yourself you can save a lot of money.

[CSY Man]

Depends. If you pull the engine and deliver it to the shop and put it back in yourself you can save a lot of money.
__________________

Yeah good idea Paul: Pull the whole engine out, the entire 600 pounds, take it to the shop for pump rebuild, then put it back in.....

I sure would save a nickel or two, but my back would be twisted..

[Alan Wheeler]

Is this excessive....?

Hell yeah.
You don't need to remove the entire engine. If you have any mechanical skills, removing the pump and replacing it afterward can be an option.

[avazquez]

The previous owner had the pump on my 4108 overhauled less than 50hrs ago. I can't believe it would cost $1500.00. I am sure I cant get much more than that if I try to sell the whole engine. What does an overhaul of the pump entail anyway ???

[CSY Man]

Hell yeah.
You don't need to remove the entire engine. If you have any mechanical skills, removing the pump and replacing it afterward can be an option.

Never thought I had to remove the engine...Not sure where that came from..

[donradcliffe]

Junior in Redhook did a good job on my pump about 12 years ago for about $600, lost more details when I sold the engine and gave away the manual with his full name and number. Getting the pump out will make you curse British engineering, as there are 3 screws holding it on--2 are relatively easy, but the third is an allen screw behind the pump and under the exhaust/heat exchanger. I ended up making a long hex tool to reach it.

[Alan Wheeler]

US$600 (NZ$1000.) would be about what I would expect.