Mercarb Rebuild Float Drop Question

[UNSUREBOATGUY]

I'm finishing up a rebuild on my mercarb # 1389-9562 (87 3.0 S/N below in signature) and have a question on the float settings. I was following the procedure in Mercruiser Service Manual #10, and the float level matches the instruction sheet that came with the rebuild kit, but the Float Drop is a bit different. Manual # 10 says 1 1/4" (or 44.5 mm-which doesn't jive with 1 1/4"-it's more like 32mm) and the instruction sheet says 1 3/32" or 27mm.

Which do I follow? This is my first carb rebuild, so I'm sorry if this is a silly question.

Thank you very much.

 

[Grub54891]

Re: Mercarb Rebuild Float Drop Question

What I do is before removing old float/seat is measure the drop before removal,the kits are a genral guide,sometimes they match,sometimes they don't.That gets ya in the genral height,then I check the instructions for their settings,usually find what I'm looking for.
Grub

 

[UNSUREBOATGUY]

Re: Mercarb Rebuild Float Drop Question

Still being new to this-how critical is the drop measurement? Does it matter a few mm one way or the other? I just want to get it right the first time.

Thanks again.

 

[Don S]

Re: Mercarb Rebuild Float Drop Question

Use the dimension in the manual.
The float drop just keeps the float from hitting the bottom of bowl. A little high won't hurt, but you don't want the float hitting the bottom.

 

[UNSUREBOATGUY]

Re: Mercarb Rebuild Float Drop Question

Thank you.

 

[Grub54891]

Re: Mercarb Rebuild Float Drop Question

If to high,it will flood the motor,use your best judgement on hight,I've not had much for issues my way,be shure to replace the float,I ad one in 20 years that looked good but was bad!

 

[Don S]

Re: Mercarb Rebuild Float Drop Question

If to high,it will flood the motor,use your best judgement on hight,I've not had much for issues my way,be shure to replace the float,I ad one in 20 years that looked good but was bad!

That is float level, he is asking about float drop. Two different things.

 

[Grub54891]

Re: Mercarb Rebuild Float Drop Question

That is float level, he is asking about float drop. Two different things.

Yup oops...