Author Topic: Marine Qjet  (Read 2719 times)

Offline Dlanzer

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Marine Qjet
« on: July 25, 2012, 05:02:36 PM »
Hello everyone, need help with trouble shooting my qjet. The boat is a 1989 with a 350 merc 260 hp. I bought it last year and the boat ran great except for hot restarts, since it was the end of the season I just lived with it. I could see fuel vapor in the primary side, and slight wetness on the boosters.
So I ordered cliffs rebuild kit, pulled carb off and tore it apart. The only things I saw that did not look right were the power piston was frozen, and the back corner of the gasket was wet.
Everything went together nicely, and put it back on.
Now I have two issues.
The first is the original issue. Hard hot starts after about 15 minutes of sitting.
The second is that I am low on power. It lays flat on its face when it's under load. It sounds like the secondaries are opening real fast. I did not adjust or change any settings other than idle mixture.
Any help would be appreciated.
Thank you
Darrell

Offline Cliff Ruggles

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Re: Marine Qjet
« Reply #1 on: July 26, 2012, 04:43:09 AM »
Did you pressure test the main casting plugs to see if they are leaking?

Is the timing advancing correctly with increased engine rpms?.....Cliff

Offline Dlanzer

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Re: Marine Qjet
« Reply #2 on: July 26, 2012, 06:07:51 AM »
I did not leak test the main casting. It had epoxy on it when I took it off, also you can see the vapor above the base plate.
No other changes were made besides rebuild kit. I did not check timing as it was running fine. It was just the hot start issue. It does start up instantly when hot up to about 10 minutes then after that i need to open throttle all the way.

Offline Cliff Ruggles

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Re: Marine Qjet
« Reply #3 on: July 27, 2012, 03:09:26 AM »
About 99.9 percent of the carbs I pressure test leak right thru any attempts at dabbing epoxy over the plugs. 

I would pressure test the main casting to see if any of the plugs are leaking?  If so, install screw in plugs coated with Marine Tex.  We sell a kit with the plugs and a generous supply of Marine Tex to fix this problem.....Cliff

Offline Dlanzer

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Re: Marine Qjet
« Reply #4 on: July 27, 2012, 05:42:09 AM »
I pulled the carb off last night, as I plan on doing the plug and epoxy. It didn't have enough fuel to come through the squirters.
After taking it apart I noticed I have the needle clip through the holes. This was how I found it originally, but after reading more about it I believe its in the wrong spot. Would this create any of my issues.
Thank you

Offline Cliff Ruggles

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Re: Marine Qjet
« Reply #5 on: July 30, 2012, 05:42:13 AM »
Yes, it can cause flooding and loss of fuel control if hooked thru the holes.

Another problem we see is leaking between the seat and the gasket if any old material or the old seal was left in place.....Cliff

Offline Dlanzer

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Re: Marine Qjet
« Reply #6 on: August 06, 2012, 08:43:19 PM »
 ;) I finally had time to put it back on and take it for a test spin. Life is good. No more hot start issues, and the bog went away.
Thanks for all the help

Offline Cliff Ruggles

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Re: Marine Qjet
« Reply #7 on: August 10, 2012, 04:49:43 PM »
Good news! :)....Cliff