Hard Starting Genset

[Dockhead]

I love my Kohler 6.5kW heavy duty, low speed genset. I had a round of problems with it which were all due to my ignorance about changing the (about the existence of) the anode in the heat exchanger, which resulted in a perforated heat exchanger which took me some time to figure out. But since I replaced the heat exchanger (at considerable expense), the genset has been back to its old, dead reliable self, chuffing away quietly for hours at a time putting out the amps, a vital function on my boat with large power demands and no shore power, as my boat lives on a mooring in the lovely Hamble River.

I only have one problem - after a few weeks of time off, it doesn't readily start. In contrast to the other Yanmar on board, which starts if you even look sideways at the key, even in freezing temperatures. After the first start after long silence, everything is normal again. But Im bothered by this - can't be good for the starter, and I often cut off the seawater intake seacock in order not to risk seawater flooding back through the muffler. Why would it be so hard to start? Could it be air leaking into the fuel system? What should I look for?

[lonesoldier0408]

Suspect any rubber lines, use paper towel to inspect all fuel lines and fittings. Check for dust collection on trails left by fuel weeping. A leak on a filter gasket could be an issue especially if any previous gasket material was missed on prepping for a new filter. A deeply gouged gasket mating surface will cause the same leak (a little JB Weld and light sanding )Cracks at banjo fittings have occurred and O-rings do fail. How old are the injectors and the injection pump ( internal wear.). Just my 2 cents. :beer:

[btrayfors]

Don't know the Kohler, but I had a problem this summer with a hard-start/no-start NextGen 3.5KW which had always started easily.

Turned out to be a sticky plunger on the "run solenoid". The solenoid when activated pulls in the plunger which itself is attached to the throttle on the little Kubota engine. It wasn't properly activating due to two things:

1. a slightly deteriorated rubber boot which was sticking around the plunger shaft; and

2. the plunger itself was not correctly lined up...it was a bit out of true.

Some fiddling, a bit of CRC lubricant and it was good as new!

Must admit, though, your problem sounds like a fuel problem. Maybe sitting for awhile allows the fuel to drain back a bit due to a tiny air leak??

Bill

[ranger58sb]

DH, I mentioned in an earlier thread that our 8EOZ is the US 60-cycle version of yours...

And ours is never difficult to start.

(Knock wood.)

Can't speculate very well about the potential problem, but I'd guess there is one. Maybe fuel-pump or fuel-line related? Gradually losing pressure (suction) over time?

-Chris

[a64pilot]

How many hours on it? Does it have glow plugs?

[Dockhead]

Originally Posted by a64pilot

How many hours on it? Does it have glow plugs?

About 1000 hours (160 when I bought e boat). No glow plugs. Three cylinder Yanmar industrial engine, 1000cc and 14 horsepower at 1500 rpm.

[Dockhead]

Originally Posted by btrayfors

Don't know the Kohler, but I had a problem this summer with a hard-start/no-start NextGen 3.5KW which had always started easily.

Turned out to be a sticky plunger on the "run solenoid". The solenoid when activated pulls in the plunger which itself is attached to the throttle on the little Kubota engine. It wasn't properly activating due to two things:

1. a slightly deteriorated rubber boot which was sticking around the plunger shaft; and

2. the plunger itself was not correctly lined up...it was a bit out of true.

Some fiddling, a bit of CRC lubricant and it was good as new!

Must admit, though, your problem sounds like a fuel problem. Maybe sitting for awhile allows the fuel to drain back a bit due to a tiny air leak??

Bill

I also suspect the pinhole fuel leak. I will investigate further.

Maybe one way to check would be to bleed the system before attempting next start. Hmmm.

[a64pilot]

1000 hours shouldn't be compression, no glow plugs to burn out, pretty much only leaves fuel, assuming of course the starter is spinning it fast enough. I've seen that before, sounded normal but hard start issues went away with tightening battery wires.

Dockhead,
I think your problem is a known issue, I'm generator looking and been reading manuals etc., anyway that solenoid and a hard / no start issue is in there under throubleshooting I believe

[a64pilot]

Oh, valves, ever checked the clearence?

[glenn.225]

Originally Posted by Dockhead

I also suspect the pinhole fuel leak. I will investigate further.

Maybe one way to check would be to bleed the system before attempting next start. Hmmm.

I seen cases where rubber lines would allow a tiny amount of air in but would not leak fuel out. If you can pressurize the fuel system 3-5 PSI for an hour or so and then have a really good look. Use paper towel as suggested, wipe everything down good before you start. I used to have a fuel cap made for this purpose.