Perkins 4108

[Rbrucek]

I can’t get the engine running. I have tried to get fuel perged of air. I can get the rear two jets to drip fuel bet not the front two. It was running fine but when it sat idle for about two weeks it must have lost prime. Any ideas?

[DougR]

Yep, the 4-108 is not the easiest engine to bleed all the air from the fuel system. You have to follow the steps in your owners manual closely....first bleed all the air from the fine filter on the engine, then there are several bleed screws on the CAV high pressure pump that need to be bled in the proper order, then finally bleed the high pressure lines to the injectors. Only then do they like to start.

If you are loosing prime and getting air into the system, that might bear looking into before you start on the engine side of the system.

DougR

[Rbrucek]

What would cause it to loose prime?

[DougR]

It could be any number of things... Loose hose clamp on a fuel hose, bad gasket or O ring on the primary filter, loose fitting on the fuel tank pickup, split hose, etc. Start at the engine lift pump and work toward the tank looking for possible air leaks in the system. Besides causing the engine to loose prime, an air leak could make it difficult to get the air bled from the system again.

DougR

[oldcal46skipper]

Read the manual and follow instructions. My partner and I rebuilt 21 Perkins 4.108's last year 2017 and we still review the manual.

As another poster advised, start at the tank and work to the engine checking for possible leaks. I had one small hole in a tank pick up tube about half way down. It ran okay until the fuel level dropped below that level.

Check it all.

BTW, anyone have a 4.108 long block that needs work, near Pensacola?
Send a PM

Tom

[Lepke]

Make sure all the air is out of the injector pump. If not, you have air in the individual tubes. The air compresses in the tubes instead of opening the injector.
Some people replace the lift pump with electric because it's makes filter changes and bleeding easier. I have a 4108 running a generator and added an inline electric pump. I still use the stock pump when running, but filling filters and bleeding is a snap. The pump was about $16 on ebay.
The 4108 is a great engine, probably the longest in continuous production engine Perkins ever built. It was made in about 25 countries under license and parts are everywhere including industrial and tractor dealers. Mine's a 1972.

[Water Dragon]

Originally Posted by Lepke

It was made in about 25 countries under license and parts are everywhere including industrial and tractor dealers.

Really? I have a 4.108, and I've had no luck at all finding parts locally in Juneau, other than fuel filters at NAPA. I've been nearly pulling my hair out as I spend hours and hours hunting around on the internet looking for parts. I sure wish I could just go to the store, tell them what I need, and walk out with it... or at least someone who would say "I don't have it, but I can get it."

[Captain Randy]

Best to use the internet and order what you need. You could have had the parts there by now lol. S&W Diesel in Long Beach, CA can take care of you.

Perkins

Happy Hunting

[Lepke]

On line is the best place for parts in a remote area. Can't speak for Juneau, but in BC (Prince George, Vancouver and Nanaimo) and lower 48 there's plenty of dealers. Larger tractor wrecking yards often have gaskets and some times engine kits. Ebay, too.

[pdxsailordiver]

Water Dragon
I get my parts from Perkins Pacific in Ridgefield Washington.
They have been very helpful and they even have 4- 107, 4- 108 core motors that I have got a few hard to find used parts off of.

[Tia Bu]

Check to see if you might have a slow leak in the fuel return line running from the injectors back to the fuel pump. You would see (and smell) a bit of leaking diesel on the rear part of the engine. I had that once and had the symptoms you describe. It was leaking at a junction. Easy repair. Good luck.

[BigAl.NZ]

Originally Posted by Lepke

Make sure all the air is out of the injector pump. If not, you have air in the individual tubes. The air compresses in the tubes instead of opening the injector.
Some people replace the lift pump with electric because it's makes filter changes and bleeding easier. I have a 4108 running a generator and added an inline electric pump. I still use the stock pump when running, but filling filters and bleeding is a snap. The pump was about $16 on ebay.
The 4108 is a great engine, probably the longest in continuous production engine Perkins ever built. It was made in about 25 countries under license and parts are everywhere including industrial and tractor dealers. Mine's a 1972.

What electric pump did you buy Lepke?

[Rbrucek]

I did not buy one, I had one. Not sure what brand it is.

[Warby12]

Originally Posted by Water Dragon

Really? I have a 4.108, and I've had no luck at all finding parts locally in Juneau, other than fuel filters at NAPA. I've been nearly pulling my hair out as I spend hours and hours hunting around on the internet looking for parts. I sure wish I could just go to the store, tell them what I need, and walk out with it... or at least someone who would say "I don't have it, but I can get it."

Also try: https://www.parts4engines.com/

https://www.asap-supplies.com/ have some and they both ship very quickly.


Best by far is https://www.tadiesels.com/ experts and nice people

[Lepke]

Originally Posted by BigAl.NZ

What electric pump did you buy Lepke?

Almost any 12v pump will work. I usually buy on eBay. Rated for diesel and about 30 gallons per hour free flow. Usually about $20. I have 4 still working at 10 years old. They're cheap, but a spare.