Perkins 4.108 Engine Trouble

[Argyle38]

Originally Posted by FionaJC

Its just a thought but I have heard of a diaphram going on the fuel pump of a Perkins 4107 /4108 and causing issues.

Yep, this happend to me.

Spent two or three years dealing with an intermittent problem where the engine would rev (mixture going lean) then quit, about 10-20 minutes after not running for a while (several hours minimum). After bleeding, the engine would start and run for as long as I kept it going, no problems.

I tried a lot of things, trying to track down the air leak in to the fuel line. Finally I saw the mechanical lift pump was for sale for only around $35, so for that it was worth a try.
Replaced the pump and the problem went away. Seems that the old lift pump had a very slow leak and when the engine sat for a while, the pull from the pump to the tank, about 3' down or so, would pull air in to the line from the leak. Eventually enough air would seep in to create enough of a air bubble that would cause the engine to quite, about the 10-20 minutes it took for the bubble to make its way to the injectors. When the engine was running, there was enough flow that any microscopic bubbles didn't matter. Only a problem when it sat for a while.

Very frustrating problem, but I got very good at bleeding the 4-108 and now I never leave the dock without the main ready to be hoisted at a moments notice.

[Lepke]

I have 2 mains and 2 generators. All have an added 12v fuel pump for bleeding and filter changes. I have a fused switch near the pump so I can control it when bleeding. When running the stock lift pump pulls thru the electric pump, but the 12v pump can function as a primary lift pump. In that case it would receive power via the ignition switch. Electric pumps are designed with only enough power to supply a few pounds of pressure and stop working when pressure is reached. Diesel engines won't flood. Excess fuel is returned to the tank. In the case of a 4108, the injector pump supplies no fuel to the injectors unless the engine is turning over.