Mercury Wmh 34/39 Carb black cap/plug

[rgsauger]

Engine Synchronization and Linkage Adjustments". Aka, link n sync

yank all of the black boxes and also ditch the oil injection and go to premix.

[Jay0016]

Someone already went to premix im assuming when it was repowered. They probably stopped trusting the oiler after it cost them a cylinder or two.

When you say yank black boxes what do you mean exactly?

[rgsauger]

There are usually one or two black boxes tied to the ignition system if not already removed. One is idle stabilization and I forget the other. Both are not needed and are crap. Look up Mercury black boxes and you’ll see what I’m referencing.

[Jay0016]

Checked on black boxes and they appear to be already be removed. Ended up buying another wmh34-1 carb. Should be here this week its cheaper than buying rebuild kits assuming the black plugs are already in the carb.

[Jay0016]

So ended up finding the same black plug part in the bom for i think the wh carbs but they are called block stuffers by mercury.

Shes back together and idling great but water test will tell the real story.

[Jay0016]

Got the boat out and did a lake run. There is a little bit of bog on the hole shot sometimes but once on plane she goes. I think my idle mixture may be a little too rich and i may be wetting the plugs but once they burn off it goes not too sure but i think its just some small adjustments to get it dailed in.

[tlwjkw]

one thing lotsa folks do that has a little bit of effect on a stutter/bog is when they are at idle they have tha motor tucked all tha way IN/Down for a distance and/or long no wake zones.. this seems ta really load up some motors... once ya get a motor started it really needs ta be at level and/or a tad positive at idle.. this works with most but not necessarily all.............. jmo

workin' tha trim for different reasons needs ta be experimented with ta find out jus what works for your rig ta be its best.....

[derekfl]

remember. this is a low pressure fuel system.. runs ok on 1 psi and carbs don't like more than 3 so i have heard. so you need NO RESTRICTIONS! make sure you can blow through it easy. including the pumper bulb!

[tlwjkw]

you can run up ta 5/6 bs if needle n seat are good.... have run up ta 8 lbs when i was in a bind............ a small car motor, carb, 'lectric pump eliminates most all fuel delivery problems..

if you want an oem manual send me an email addy and ill send ya a pdf file for it....................

[Jay0016]

Thanks for the advice on the trim, the motor does tuck under the boat a bit when trimmed all the way down so ill keep that in mind next time im out idling around.

I did replace the entire fuel system, knocked out check valve, replaced all hoses and put a new pulse pump on. I did think about going to an electric pump before hand so maybe ill try that as well.

Going to go through the cooling system next i think something broke or clogged up when i was running.

What pitch prop you guys running on these motors? Got a 24p tempest with porting on it.I was able to spin it up to 6k on my tach before hitting optimal trim/full throttle. Not 100% sure the tach is right either though.