| Author |
Message |
    
Jeff Wilkinson
Member
Username: kencraft21
Post Number: 4
Registered: 07-2009
| | Posted on Saturday, July 11, 2009 - 09:36 am: | 
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motor is idleing at 1000 rpms with no back pressure, motor wants to fall back to 800 then back to 1000, what should normal idle be with back pressure or without and do you adjust idle with timing screw, thanks again for any help |
Graham Lamb
Senior Member
Username: galamb
Post Number: 5610
Registered: 05-2007
| | Posted on Saturday, July 11, 2009 - 02:33 pm: |
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Once the idle is initially adjusted either from factory or after replacing parts you should never have to touch it simply from "normal" use.
You may be able to fiddle with it and take care of the slow surge you are experiencing, but that is simply putting off dealing with the issue causing it (which could be anything from old fuel to a fuel pump starting to go, a clog forming in the fuel system to numerous other causes).
Idle, in forward gear, should be 650 +/- 50 rpms and in neutral approx 100 rpms faster. |
Jeff Wilkinson
Member
Username: kencraft21
Post Number: 5
Registered: 07-2009
| | Posted on Sunday, July 12, 2009 - 08:40 am: |
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idle is at 750 to 800 out of gear, took the boat out yesterday, under a load motor run good, just having a hard time at idle, motor would cut off at times at idle, would need to idle motor around 1200 rpms to keep it running but not at all times, if it is fuel, would i not see other issues? thanks again for any help!! |
Graham Lamb
Senior Member
Username: galamb
Post Number: 5619
Registered: 05-2007
| | Posted on Sunday, July 12, 2009 - 12:35 pm: |
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If it runs good "other" than at idle, that is normally indicative of a clogged/partially clogged low speed jet - which generally only affects the idle - and most notably "under load" - and would also explain the uneven idle... |
Jeff Wilkinson
Member
Username: kencraft21
Post Number: 6
Registered: 07-2009
| | Posted on Sunday, July 12, 2009 - 03:38 pm: |
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thanks graham i will clean carbs monday, will let you know i it's comes out thanks again will talk later |
Jeff Wilkinson
Member
Username: kencraft21
Post Number: 7
Registered: 07-2009
| | Posted on Tuesday, July 14, 2009 - 06:32 pm: |
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hello graham, cleaned carbs found some rubber looking stuff, took inline filter off, new as of 3 weeks ago, a lot this stuff, dumped water sep. non of this stuff, could this be fuel pump bladder gone bad? if it is, would motor still run good under a load, idles fine for a few min. then starts doing the same old thing. would that be all the fuel as been ran out of the bowls? got me thanks again for any help |
Graham Lamb
Senior Member
Username: galamb
Post Number: 5648
Registered: 05-2007
| | Posted on Tuesday, July 14, 2009 - 10:32 pm: |
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It could be the fuel pump diaphram going on you or it could be one of your fuel lines coming apart from the inside out.
I would replace the fuel line from the connection over to the fuel pump, just incase - you can pick up a piece of bulk hose from any discount auto parts place for a couple bucks a foot... |
Jeff Wilkinson
Member
Username: kencraft21
Post Number: 8
Registered: 07-2009
| | Posted on Wednesday, July 15, 2009 - 06:40 pm: |
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good afternoon graham, i rebuilt carbs, not much change in idle, better but not good. what are the air mixture screws settings, do you know? it is like the carbs are loading up trying to chock the motor out, thanks again |
Graham Lamb
Senior Member
Username: galamb
Post Number: 5667
Registered: 05-2007
| | Posted on Thursday, July 16, 2009 - 12:34 pm: |
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The three carb banks are a little different, each carb has two idle screws (one over each throat).
The top pair (cylinder 1 and 2) are 1 1/2 turns counter clockwise from "lightly seated" then you can fiddle about 1/8 of a turn to get them fine tuned.
The other two carbs (for cyl 3,4,5 and 6) are 1 7/8 ccw from lightly seated +/- 1/8... |
