Perkins 4.108 starting problem

[roberttigar]

I've run out of ideas. My 4.108 is difficult to start-only on the first start of the day. This has nothing to do with the air temperature. For the last 6 months, whether its 85' or 65', the first start of the day requires a lot of grinding. Once it starts, I can shut it down and then restart immediately.

Air screen is clean, filters clean and there is absolutely no fuel leaking. Injectors have been serviced. have no cold start equipment installed.

The engine runs fine, power is good, no excess smoke, no strange noises. Its just this problem that has me scratching my head.

I have got to be overlooking something. I'm not beyond calling a mechanic. I'd just hate to have overlooked some small item that would require shelling out a couple hundred dollars and make me feel real foolish for missing it.

Anybody got any ideas?

Bob

[unclemack]

Sometimes the weight of diesel in the fuel line is enough to suck air in.
Some people refuse to believe that air leaking in doesn't necessarily mean fuel must also be leaking out but it happens.

Lift pump can sometimes let diesel drain down.

Cheap non-return valves are available - one in the fuel line below the lift pump would prevent the slow starting... IF one of the above is the cause of it

Better to find the leak of course but that can be time-consuming with limited equipment.

[Emmalina]

I would hazard a guess at you needing an injector pump rebuild ! Always been my cure for start of the day slow starting diesels

[Snowpetrel]

Had a similar problem with my nanni. It turned out to be air leaking in through the injector pump return line. I fitted a valve into it and problem solved.

Try turning off your fuel valve at the tank after running. This might solve the problem, then you know it's draining down overnight.

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[CSY Man]

Originally Posted by Emmalina

I would hazard a guess at you needing an injector pump rebuild ! Always been my cure for start of the day slow starting diesels

Yeah, I concur.
Unless the problem started overnight.
I had the same on my 4-108: Over the years it took a little longer to start, slowly but surely. I poked around, overhauled injectors, set valves, even installed an Anderson electric boost pump to pressurize the feed lines. No difference. Kept asking experts, same answer more than once: High pressure pump may need an overhaul...

[zeehag]

4-108?!!!
check your engine kill lever on the injector pump. the cable could be not working and no go ever. mine did that just now--took a week of asthma to find it ...

[bsurvey]

take an oil sample it may help. had the same problem found i had a head gasket leak as I had sodium in the oil. a little water with salt will dry on the piston crown and will have a hard time starting once burned out and warm the head and block metal swell & seal due to the heat so it only happens when it is cold

[KadeyKrogen38]

The Perkins Manual recommends full throttle on starting when cold. I do not use full but do give it some throttle. Never have not started quickly when using a little throttle on first start up.

[boeing1]

agree, if it is only happing on the first start of the day. I would check for air getting in fuel line

[Simonfla]

I have same problem ,motor was running great I've just serviced motor by changing oil ,oil filers and fuel filters ,motor bleed and started fine after but now if I leave it for 24hours or more it takes 15 seconds to start as if air was in the fuel line ,searched all over its somewhere behind lift pump the problem ,I'm having a diesel mechanic check it out


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[Steve Bean]

Could the "draining-down" theory be tested by temporarily installing a small fuel tank above the engine? Not hard to do...

[roberttigar]

Simon, Please let me know what you find out and I will do the same. This is frustrating. All-in-all, except for this problem, the engine is running better than ever.
Bob Tigar bjtigar@att.net

[BruceS]

I always check oil & water before starting if it's been more than a few days since starting.
While I'm down there I give the lift pump about 10 pumps by hand. Solved my slow startups. Yep, draining back a bit ....
Considered installing an electric lift pump .... that'd fix it too?

[Barney21]

The one way valve should fix it. However if you want to be more positive an electrically operated on/ off tap wired into the positive circuit, the tap after the lift pump. Modern diesels have a solenoid that shuts off the diesel to stop the engine. These are expensive ,and are harder to fix ( impossible)! so the electric tap is easier, I use them on tractors when the Solenoid ones die. They are cheap and do the same job.
If your throttle control is not shutting completely when you turn off the engine this will allow the fuel to bleed back.

[Simonfla]

One other idea is to put a 12 volt fuel pump on the fuel line before the filters attached to the ignition switch so when you turn the key the pump pressurizes the fuel line before you press start .Also really handy when bleeding the fuel lines after changing filters


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