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Offline hotrodelrod

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07 Mokai with EX21 upgrade shutting down
« on: August 01, 2017, 06:56:04 PM »
As the title stated my 07 with Toms ex 21 upgrade is giving me trouble.Performance Mods are Toms clutch and exhaust(not water cooled) After a short run (a few minutes) at full throttle the engine sputters and ultimately shuts down. Only after it rests for a spell will it re-start. I disassembled the carb and cleaned as per the video. Did not help the problem. I'm guessing its heat related. Also, i find that while under full throttle I need to "play with" the choke control to find a sweet spot where the motor runs best. Its been a frustrating time as I dont get to run the mokai often and when I do I have these problems. Gas is fresh, carb is clean, plug is good etc. Can someone please tell me what I am missing? My buddy still has the Honda and pull start in his and he runs better and faster. I am 20lbs heavier.
Thanks for any input,
Rick

Offline Painlesstom

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Re: 07 Mokai with EX21 upgrade shutting down
« Reply #1 on: August 01, 2017, 07:20:09 PM »
Sounds like it's starving for fuel. Check your fuel line connector to the tank, it should have an o-ring on the end to seal it. If that is damaged or lost, the fuel pump will suck enough fuel to idle but not enough to run full throttle.
Tom

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Offline happul3

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Re: 07 Mokai with EX21 upgrade shutting down
« Reply #2 on: August 01, 2017, 07:55:05 PM »
Can it be running very lean because of pulse line fitting completely loose?

Offline Painlesstom

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Re: 07 Mokai with EX21 upgrade shutting down
« Reply #3 on: August 01, 2017, 08:00:46 PM »
Can it be running very lean because of pulse line fitting completely loose?

This is one of my conversions, my pulse fittings don't come loose. ;)
Tom

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Offline hotrodelrod

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Re: 07 Mokai with EX21 upgrade shutting down
« Reply #4 on: August 01, 2017, 09:06:58 PM »
Sounds like it's starving for fuel. Check your fuel line connector to the tank, it should have an o-ring on the end to seal it. If that is damaged or lost, the fuel pump will suck enough fuel to idle but not enough to run full throttle.

Thanks for the response Tom. So if both of my fuel tank connections are not sound this could be the issue? I ask because I recently replaced the vent side hose fitting and I could not get it to snap into the tank side fitting completely.I discovered, once back home, that the tip of the old fitting was broken off inside. It appears that the fuel side fitting is sound.

Thanks

Offline Painlesstom

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Re: 07 Mokai with EX21 upgrade shutting down
« Reply #5 on: August 01, 2017, 09:44:20 PM »
Very possible that is the problem. Those connectors are valved, meaning when they are not hooked together the flow is shut off.. on both sides. So if the vent side fitting is broken, the valve wouldn't be opened when connected and the tank wouldn't be able to vent. The fuel pump is drawing against a vacuum, the flow stops, and the engine starves.

http://quickcouplings.net/osc/product_info.php?cPath=21_23&products_id=51

http://quickcouplings.net/osc/product_info.php?cPath=21_23&products_id=82
Tom

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Offline The Man

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Re: 07 Mokai with EX21 upgrade shutting down
« Reply #6 on: August 01, 2017, 10:14:54 PM »
You could temporarily loosen the gas cap to vent. But I would avoid rough water. You could also empty the fuel to a half tank.  Just a suggestion to see if it is a vent issue, not a fix by any means.

Offline Painlesstom

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Re: 07 Mokai with EX21 upgrade shutting down
« Reply #7 on: August 01, 2017, 10:17:55 PM »
Yes, I should have mentioned that. Thanks Shawn.  \./8
Tom

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Offline hotrodelrod

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Re: 07 Mokai with EX21 upgrade shutting down
« Reply #8 on: August 02, 2017, 08:40:03 AM »
Thanks guys. I'm going to try to get out this afternoon and will report back. I'm thinking that venting is not the issue as I thought to leave the cap loose previously but maybe not loose enough?

Rick

Offline Painlesstom

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Re: 07 Mokai with EX21 upgrade shutting down
« Reply #9 on: August 02, 2017, 08:34:25 PM »
Did you get a chance to test it again today?
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Offline hotrodelrod

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Re: 07 Mokai with EX21 upgrade shutting down
« Reply #10 on: August 05, 2017, 07:57:23 AM »
I wasn't able to get out until yesterday. I did make some more changes/improvements during the week though. I upgraded my starter wiring to 8 gauge wire soldering all connections and installing a disconnect in line copying Tom. Works 10x better, no hot wires! lol I also finally installed my steering swap kit as per the you tube video. Love it! Now to the fuel issue.......While running on the bench I noticed a fuel leak (steady drip) coming from the carb area. I snugged up the bowl and 2 bolts that attach it to the motor and it seemed to go away. Got away from work early yesterday and headed to the river (Shenandoah) Boat fired right up and I headed up river, grin on my face as it was running smooth. Speed checked on gps at 8-9 mph. (I am 210, 3/4 tank, cooler with ice and drinks, bottom beat to hell and back from ledges) so I am happy! 2 minutes later it starts sputtering! I ease off the throttle and it runs better. I now smell gas! I get over to shore to have a look and cant see gas leaking but sure as heck smell it. Now don't judge me here but I make the (stupid) decision to forge forward as I dont get out often. I dump a little water in "bilge" and forge on. This went on the rest entire afternoon. Run well, sputter, stall as it wont idle. Would only start with throttle wide open. I'm sure all due to fuel leak so I plan on removing carb and starting over. At least I got out?

Offline hotrodelrod

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Re: 07 Mokai with EX21 upgrade shutting down
« Reply #11 on: August 05, 2017, 08:08:41 AM »
Forgot to mention that I also removed pull starter from flywheel for better cooling.

Offline Painlesstom

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Re: 07 Mokai with EX21 upgrade shutting down
« Reply #12 on: August 05, 2017, 08:11:51 AM »
Sounds like the float needle is leaking and causing flooding. Hopefully a good cleaning will solve the problem. Fuel pump could be causing problems too, have seen that many times. 10 gauge wire is all that is needed for the battery wiring, if that was getting hot you were cranking too long or something else is wrong.
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Offline hotrodelrod

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Re: 07 Mokai with EX21 upgrade shutting down
« Reply #13 on: August 05, 2017, 08:34:42 AM »
as for the wiring I was using 14 gauge and it was wired incorrectly. It worked but struggled. Great now. Can I test the fuel pump?

Offline Painlesstom

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Re: 07 Mokai with EX21 upgrade shutting down
« Reply #14 on: August 05, 2017, 08:59:32 AM »
Ah, ok. That was one of the conversions I did not do the wiring on then. 14 awg was definitely too small, when I said 10 gauge I was remembering what Mokai uses, I use 8 and you were right to use that too; I can imagine how much better that works now!

The only easy way to test the fuel pump, is to swap in a new one and see if there is a difference. Hard to test it when the motor has to be running to supply the pulse signal.
Tom

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