possible leanness?

[yankeeboy]

Ive noticed lately that my superjet wants to build up rpm's when the pump isnt loaded. When its on the trailer, or even during jumps it wants to slowly rev up. My idle isnt set very high. I was told its lean, what do you guys say and how to fix?

83mm bore
mild BCW freestyle port
150 compression
dual 38's (oem F/a) they were 'opened' at the top, but not 'taper bored'
75 low
95 spring
137.5 high
1.5 n/s
filled crossover

 

[Mark44]

Sounds like you could have an air leak if it was running fine before this issue.

Mark44

 

[yankeeboy]

I think its been this way since i put it in, i just started to notice it when someone mentioned my high idle. Could i possibly richen up the idle?

 

[Mouthfulloflake]

tune the lo speed adjuster with the boat in the water, up against the trailer or something ( to hold it still)

get the smoothest fastest idle you can get with the adjustor screw only, then set the idle speed you want with the idle stop screw.

thats usually pretty close to easy starting and decent bottom end if the lo jet is sized correctly, and everything else is in the ballpark.

 

[Mark44]

Just like mouth said but with a tach. Run up the RPM's as far as they will go with the low speed adjuster and if you are two turns out and it was still increasing you need to up the jet size. Do this until you have no RPM increase.

I believe two turns on stock carbs is the max correct me if I am wrong.

Mark44

 

[Mouthfulloflake]

I think it depends on the carb, some adjustor screws have different pitch threads.

but yea, at some point it becomes ineffective.

My kill switch stopped working this weekend.

I screwed the pilot adjustor ALL the way in to kill it.

it worked, but when I restarted it ( pilot still in) it ran away lean like he saying, was gaining RPM.

I yanked the fuel hose off, and it sputter out.

 

[Mark44]

i

I think it depends on the carb, some adjustor screws have different pitch threads.

but yea, at some point it becomes ineffective.

My kill switch stopped working this weekend.

I screwed the pilot adjustor ALL the way in to kill it.

it worked, but when I restarted it ( pilot still in) it ran away lean like he saying, was gaining RPM.

I yanked the fuel hose off, and it sputter out.

SCARY I hate that!

 

[Mark44]

I think stock is fine 2 turns and after market is 1.5 turns

Mark44

 

[yankeeboy]

Just got back from the water, and the revving is gone ( I didnt touch anything)?? Its back to normal. But the water was also probably 30 degrees warmer than last week, and my engine was running hotter.