Author Topic: High idle  (Read 5744 times)

bigdav

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High idle
« on: May 07, 2013, 06:22:21 AM »
So I just bought My first fl350. I am having a problem with the idle. when I get on the gas and let back off, it takes about 20 to 30 seconds to idle back down. I have rebuilt the stock carb, rebuilt the engine thinking it was bad seals, all new gas line and messed around with the jets in the carb. Anybody have any ideas??

LiveWire

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Re: High idle
« Reply #1 on: May 07, 2013, 06:37:17 AM »
If the choke is on, does it change? Turn in the air bleed screw and see if that makes a difference. If the air bleed does not, I would check the size of the slow jet and see if it is clogged.

bigdav

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Re: High idle
« Reply #2 on: May 07, 2013, 07:12:44 AM »
I have gone through the carb about 10 times and had the air screw set all over. the choke just floods it out. The pilot and main are bask to stock sizes.

LiveWire

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Re: High idle
« Reply #3 on: May 07, 2013, 07:34:40 AM »
What were they when they were not stock? If the previous owner changed the jet size to compensate for another modification, changing back to stock could cause problems.

Not dropping back to idle quickly indicates a lean condition for low throttle opening. It could be because of an air leak or because of a plugged pilot jet among other things. Have you checked for air leaks? Just because it is rebuilt does not mean there are no leaks. You could spray carb cleaner around the intake and base gaskets while idling to see if there is a change.

bigdav

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Re: High idle
« Reply #4 on: May 07, 2013, 08:03:37 AM »
I have gone everyway with the jets, went so big with the pilot that it would just flood out. I have even tried a different carb that came off a running machine and it would still do the same thing. I already checked for air leaks, even had the engine apart and resealed everything. I am at a loss.

LiveWire

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Re: High idle
« Reply #5 on: May 07, 2013, 08:16:15 AM »
You have an air leak. Since that is not the answer you want to hear, I guess you are on your own.

bigdav

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Re: High idle
« Reply #6 on: May 07, 2013, 08:37:06 AM »
I realize there is a air leak some where, I was just trying to see if anyone had ideas that I did not think of. Sorry.. Is there a common place that they leak??

LiveWire

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Re: High idle
« Reply #7 on: May 07, 2013, 10:52:54 AM »
Most common are seals, cylinder base gasket, reed gaskets. Brand new seals and brand new gaskets will leak. Seals need to have to be lubricated when installed or they can fail before oil gets to them. If there is a groove in the shaft, they won't seal. You can recess the seal some so it rides in a different spot on the shaft. You say you leak tested. You pressurized the engine with 6 PSI of air and checked how long it would hold?

bigdav

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Re: High idle
« Reply #8 on: May 07, 2013, 05:17:47 PM »
the reason why it was rebuilt is because it was doing the same thing. the petcock was rotted away on the inside of the gas tank and I put a bigger pipe inside to pick up the fuel, would a bigger pipe in the tank deliver to much gas to the carb and make run like this?

LiveWire

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Re: High idle
« Reply #9 on: May 07, 2013, 05:36:37 PM »
If it was preventing the carb from getting enough fuel. Loop the fuel line up high then back down with a big filter as a reservoirnto see if it stays full. The factory routing has the filter before the pump. I put it after because it is easier to push fuel through than pull it through.

bigdav

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Re: High idle
« Reply #10 on: May 08, 2013, 07:38:45 AM »
the filter stays full, until you shut the engine off. the gas line and filter are new. what about the timing?

LiveWire

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Re: High idle
« Reply #11 on: May 08, 2013, 10:29:43 AM »
The CDI either works or doesn't. The pickup is hard mounted.

bigdav

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Re: High idle
« Reply #12 on: May 09, 2013, 08:19:41 AM »
what has to be done to do a leak down test?

LiveWire

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Re: High idle
« Reply #13 on: May 09, 2013, 10:23:34 AM »
http://www.aftershockmotorsports.com/Honda-FL350R-Odyssey/Tools/Air-Leak-Tester

You have to plug the exhaust and the intake. In the case of the setup linked, the intake is plugged with a fitting connected to a gauge and a valve. You pump in 6 PSI with a bicycle pump then remove the pump. lt should take at least 6 minutes to leak out. I prefer much longer. If there are leaks, spray the engine down with soapy water and look for bubbles.

With a running engine, you can spray carb cleaner around various gaskets to see if the idle changes. The seals are hard to check. In theory, you could spray carb cleaner in the counter balancer fill to test the PTO side seal and in the vent hose above the starter to check the right side. Not sure if that really works though.

shoubadaba

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Re: High idle
« Reply #14 on: May 09, 2013, 08:34:22 PM »
It could be as simple as the cable covers not being tight and leaking. Check the rubber covers on the top of the car the one on the trottle cable and the choke cable. They are about an inch and a quarter long and cover the cables as they enter the carb if they are not tight then it will cause what you describe.