merc 20 hp 4 stroke carb issue

Have a question about your motor? All motor talk and questions go here.
User avatar
RaisedByWolves
Posts: 520
Joined: 07 Oct 2017, 19:26
3
Location: Bucks county PA.

merc 20 hp 4 stroke carb issue

Post by RaisedByWolves »

marlattrr wrote: 07 May 2021, 12:26 I replaced the gaskets.

The only thing I didn't replace is the accelerator pump assembly.
How tight did you tighten the bolts?


A little counterintuitive, but over tightening the bolts can also cause a leak, even on a new gasket as it deforms the mounting surface deforming the gasket.
Sailbad the Sinner

User avatar
RaisedByWolves
Posts: 520
Joined: 07 Oct 2017, 19:26
3
Location: Bucks county PA.

merc 20 hp 4 stroke carb issue

Post by RaisedByWolves »

nccatfisher wrote: 07 May 2021, 14:48
marlattrr wrote: 07 May 2021, 12:26 I replaced the gaskets.

The only thing I didn't replace is the accelerator pump assembly.
^^^^^^^ I am assuming what you are describing here is the choke?
Im thinking primer, which could cause issues he described.
Sailbad the Sinner

nccatfisher
Posts: 666
Joined: 04 Feb 2013, 22:11
8

merc 20 hp 4 stroke carb issue

Post by nccatfisher »

RaisedByWolves wrote: 07 May 2021, 15:09
Im thinking primer, which could cause issues he described.
[/quote]Yep, I am still old school and call them chokes but you are correct. I was wondering if that may be the root of his evil. I know if you don't fully close/shut them off they will allow air in the system and cause all kind of problems.

marlattrr
Posts: 54
Joined: 22 Feb 2014, 16:40
7

merc 20 hp 4 stroke carb issue

Post by marlattrr »

how do i adjust or check that primer? i backed off the nut so that its not engaging at all and i still have the problem

User avatar
RaisedByWolves
Posts: 520
Joined: 07 Oct 2017, 19:26
3
Location: Bucks county PA.

merc 20 hp 4 stroke carb issue

Post by RaisedByWolves »

marlattrr wrote: 10 May 2021, 16:29 how do i adjust or check that primer? i backed off the nut so that its not engaging at all and i still have the problem
Not being familiar with that motor I couldn't hazard a guess.

You could try and disassemble it and look for a torn o-ring or diaphragm etc.

Something causing your issues should stand out.
Sailbad the Sinner

marlattrr
Posts: 54
Joined: 22 Feb 2014, 16:40
7

merc 20 hp 4 stroke carb issue

Post by marlattrr »

New carb from Amazon and shes purring like a kitten again.

Idk whats wrong with the old carb but that did it.

User avatar
RaisedByWolves
Posts: 520
Joined: 07 Oct 2017, 19:26
3
Location: Bucks county PA.

merc 20 hp 4 stroke carb issue

Post by RaisedByWolves »

Well, at least we were on the right track. :wink:
Sailbad the Sinner

marlattrr
Posts: 54
Joined: 22 Feb 2014, 16:40
7

merc 20 hp 4 stroke carb issue

Post by marlattrr »

Thanks for all the help everyone.

By the way-wolves. Im just one county north of you in Lehigh.