Kohler Gen-Set problem

[navigator336]

I'm not sure this is the best forum for this issue, but it is an engine problem. I have a Kohler 6.5 CZ23 generator. It recently has been hard or impossible to start. I've had the local authorized guys down to work on it. They have replaced a couple of things that probably needed to be replaced, but didn't fix the problem. The gen-set will sometimes run, but only as long as the start switch is engaged. On other occasions, it will run, but is running too rich. The mechanic replaced the air filter, changed the plugs (fouled due to over rich condition) and ordered a new governor spring. He said he had it running fairly well after replacing items one and two and tightening up the current gov. spring. It wouldn't start for me. However, I tried manually forcing the choke open (it's solenoid engaged) during the start cycle. It fired right off. O.K. given the over-rich condition (as determined by the famous smell technique and gas slick on the water by the exhaust), I pulled the carb (10 hp Honda 4 stroke with side draft carb). All passages were clean and open, the float needle was in good condition, etc. However, there is a galvanized steel 1/8" diameter tube running from the carb intake adaptor elbow to the intake manifold just downstream of the carb. There was a little rust in the end of the tube. I found a 99.5% block in the tube (rust). I got it open by soaking it in penetrating oil and then heating it with a torch. I haven't put it back on yet so I don't know if this was the issue with the over rich condition. I don't have a manual, but it appears to me that this tube is in effect the float bowl vent overflow return. However, unlike a down draft carb, it is returning the excess fuel directly into the manifold rather than into the carb. Now, I'm thinking (or maybe grasping at straws) that when the fuel bowl is not over full, that this tube would lean out the mixture. For sure it must increase the air ratio when the choke is closed. I've found Kohler to be a difficult company when it comes to tech support, so I would appreciate your thoughts on this.

 

[JB]

Re: Kohler Gen-Set problem

Moving to Non-Boating Tech Topics

 

[DJ]

Re: Kohler Gen-Set problem

navigator336,<br /><br />I'm no genset expert but, I suspect that your suspicions about that tube are correct. It sounds as if it is a carb fuel bowl overflow just like on a carbureted marine propulsion gas engine.<br /><br />I'm not so sure it would have an effect on the mixture, while running.

 

[bob58]

Re: Kohler Gen-Set problem

don't no much about Kholer but if it is similar to Onan, open the enrichner adjustment cover.<br />Inside of it should be a heat/resistance spring on a plate inside and they burn out. Needed to replace mine on one of my Onan's.<br /><br />Also, the Idle circuit has a very small passage that gets gummed up and plugs if run out of fuel or if fuel sits in there for awhile. Will cause it to run rich and load up and surge like the Governor is seeking the right RPM and won't stabilize.<br />A good tanking might cure it with a compressed air back.

 

[Capt Ken]

Re: Kohler Gen-Set problem

OK, you may have several problems. On the run only in the start position: The ignition system won't swap over from start to run unless the engine is putting out 12 volts. The CZ model is a capacitor discharge unit and if the rpms is off, then it don't make AC power. This can be checked my moving the governor linkage a little to see what happens. A voltmeter won't work because until the engine hits that magic rpm, it won't produce anything. The running rich could be from the fuel pump over pressuring the carb. Kohler had a problem with that some years back and those with the problem was installed with a pressure regulator to reduce the pressure. If the choke is working properly, it will kick back and forth as you attempt to start. If its not kicking back and forth, the choke board is malfunctioning. These units are different from other gensets in many ways. You are correct in Kohler being difficult. I dropped the line after being with them for 12 years due to non support when it came to customer service. JB should have moved this to the inboard section being a genset would better fit an inboard question.

 

[navigator336]

Re: Kohler Gen-Set problem

DJ, Capt-n-Bob, Capt Ken,<br /><br />Thank you all for your input. I will put the carb back on this weekend and see what happens. Capt Ken, the choke works as you describe it should (kicking back and forth). When I have gotten the thing running, a used a volt and hertz meter to check the output. It bounced around some but generally was around 110VAC and 60 hz. The fuel pump overpressure makes good sense as a potential culprit. What pressure should it be putting out? What does the screw that looks like an idle mixture screw do? It appears, circuit wise to be an air bleed. Is this so? It's currently set at 2.5 turns out. I am planning on experimenting with this as well. Thanks again for your help!