any ideas what would cause a motor to run wide open with hood off but..

kridge

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Oct 11, 2009
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i have an 84 60hp johnson...when i took it out yesterday after cleaning carbs and installing carb kits...it all of a sudden wouldnt run out when wide open...but idles fine...when i take the hood off it runs out perfect...any suggestions as to this problem would be greatly appreciated :) ty
 

R.Johnson

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Re: any ideas what would cause a motor to run wide open with hood off but..

How did this engine run before you cleaned the carbs'? Does the hood by chance have a foam blanket that is starting to hang down? This problem is usually caused by exhaust gases being drawn in under the hood. I'm trying to visualize how that could happen on your engine.
 

jay_merrill

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Re: any ideas what would cause a motor to run wide open with hood off but..

The air intake on that hood is probably at the lifting handle on the top, back of it. Any chance that you got something clogged in it from the inside, when you had the hood off?

I agree that exhaust gases getting into the enclosed cowl will affect performance quite a bit, but that's not something that would be expected to begin, just because to hood was off and the carbs were worked on. That said, just as air full of spent fuel/exhaust gases will degrade performance, so will lack of air at all. If plenty of air is not getting into the cowl from the outside, engine performance will suffer greatly.



???
 

kridge

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Re: any ideas what would cause a motor to run wide open with hood off but..

before i cleaned carbs it sat for 6 months and wouldnt start...i cleaned carbs and went for a test run...on that time it also wouldnt run full throttle either but i noticed gas was over flowing from carbs...so i pulled back apart and installed new needle and seat and floats...now i have no gas over flow but still doesnt run when full throttle...whats strange is if i keep holding at full throttle 1 time it actually cleared up and took off but if you let out of throttle and throttled back up it was back to way it was before but if i stayed in it, it would keep going full speed...how i noticed better with hood off i decided to remove it while driving back to dock and it ran perfect when i did...i could stop dead in water and hit it and it would take right off like nothing was wrong...i thought something was clogged in air hole on hood so by looking up in it i see nothing restricting it...the hood does have a foam lining but is only on sides...
 

kenmyfam

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Re: any ideas what would cause a motor to run wide open with hood off but..

Hood on and issues
Hood off and O,K,
Only 2 things spring to mind.

1, Air access to intakes restricted with hood on
2, Plug wires grounding out to hood when hood on.
 

LongLine

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Nov 2, 2008
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Re: any ideas what would cause a motor to run wide open with hood off but..

Make sure you don't have a wasps nest in the cowling handle at the back (top) of the engine. I had one and it blocked the air flow something fierce.

Tom B.
(LongLine)
 

LongLine

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Re: any ideas what would cause a motor to run wide open with hood off but..

Another thought...you didn't pinch a hose when you put cover on did you? I've done that too.

Tom B.
(LongLine)
 

CharlieB

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Apr 10, 2007
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Re: any ideas what would cause a motor to run wide open with hood off but..

Customer kept pulling the plug wire off #3 every time he put the cover on. Kept calling me out cause it wouldn't run right.

Zip tied the wire out of his way.
 

jay_merrill

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Re: any ideas what would cause a motor to run wide open with hood off but..

I think the guys have the right idea in regard to wires. I would say that the hood is catching a plug wire or other ignition system wires, when you put it on the motor. Check the plug wires at both ends and look for other ignition wires (powerpack, etc) that might be catching on something.



???
 

bob johnson

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Re: any ideas what would cause a motor to run wide open with hood off but..

I also say look at the wiring contact , especially the plug wires interfering with the hood.

i say that because i have had a lot of issues with my motor this past week and i took the hood off many many times...

the hood would not seat about half the time and i couldnt get the rear latch and the front latch both on...

turned out a spark plug wire was getting caught in a very close fitting area....

i keep the plug wires down or in a nice clear area, and the hood goes on easily every time.

PS: i cleaned four big wasp nests out of the opening in my 2001 johnson 50 hp this past summer......two were actually MUCH bigger than the opening and had to be chopped up before they would come out

bob
 

kridge

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Re: any ideas what would cause a motor to run wide open with hood off but..

well i took a look at it again and it seems to have an exhaust leak coming from somewhere...while running i pulled off the hood and you can see smoke when reving engine...looks to be coming from the right side somewhere....
 

jay_merrill

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Re: any ideas what would cause a motor to run wide open with hood off but..

If by "right," you mean the starboard side, you probably need to replace the base gasket. If its coming from the port side, the smoke could also be coming from the bottom of the exhaust cover.



???
 
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