WMV carb jetting

**nickirsch** · 06-30-2020, 05:36 PM

I have a 1996 2.0 150 with wmv-2 carbs on a 16' sidewinder. Current jetting is stock with 74 mains and 34 idle air jets and 38 in #5. Backdraft vents removed. Had trouble with a hesitation on accelerating, unless you hit the throttle just right it would die. After much troubleshooting and unnecessary maintenance i've managed to fix the hesitation completely by simply enriching the idle mixture screws. They are now out 2 1/4 turns vs the recommended 1 1/2. I also found the timing advance arm was very sticky and not advancing properly, lubed it up and now works as it should. Runs excellent off idle and now accelerates extremely well. Can go quickly to full throttle with zero hesitation. The problem now is it is idling too rich, always having to start with the fast idle lever and wont idle for long without the lever raised before it dies. Not a huge problem but would like to get it dialed in. Link and sync has been done as per the manual and timing is set. Thermal air valve is functioning properly. Carbs have been cleaned in an ultrasonic and rebuilt, floats set as per manual, level with the gasket surface when held upside down.

Instinct tells me to just go up a size or 2 on the idle air jets to lean it out a bit at idle, though i'm not clear on what affect this might have in other areas. I've also read on this forum it's recommended to go down on the idle air jets and up on the mains in these carbs to richen it throughout.

Any help is appreciated!

**Merc 2.5** · 06-30-2020, 06:38 PM

The stock jetting should b just fine with stock motor , unless in crazy elevation or sumthin. Does this motor still have idle stabilizer/ black box ? Sumthin just seems off besides jets

**nickirsch** · 06-30-2020, 06:51 PM

That's what i thought, quite confused. Idle stabilizer has been removed. I think i need to do some more adjusting of the idle mixture screws to find a sweet spot where I don't get the acceleration issue and an improved idle.

**tlwjkw** · 06-30-2020, 07:07 PM

how did you set "idle timing"?.. needs ta be done in tha water, in gear.. do you have a "gap" between throttle cam and carb roller?

**nickirsch** · 06-30-2020, 07:15 PM

Originally Posted by tlwjkw

how did you set "idle timing"?.. needs ta be done in tha water, in gear.. do you have a "gap" between throttle cam and carb roller?

Yes I set the idle timing in the water and in gear. Have it at 0 right now, the further ATDC the worse it gets. I have a small gap between the cam and the roller, about 1/8".