idle rpm for merc 150

B

b0mbtrack

Petty Officer 1st Class
Joined
Mar 26, 2007
Messages
269
i have a merc 150hp black max, 1984 6 cyl. I want to lower the rpms, is there anyway of doing that without having to re-sync the whole engine?
 
tashasdaddy

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: idle rpm for merc 150

you have a idle stop speed screw. it stops the linkage, at low speed. mercurypartsexpress.com look at the diagrams.
 
j_martin

j_martin

Admiral
Joined
Sep 22, 2006
Messages
7,474
Re: idle rpm for merc 150

It's a good idea to go ahead and check out the link n sync. If you set it up right, Idle will probably fall in very close, and a small adjustment of the idle stop screw drops it in.

I bought an 18 year old Black Max that had been the victim of quick fixes for years. When I got it timed up right, fuel mileage increased dramatically, as did power. The throttle cable was close to 1/2 inch off, couldn't even be hooked up without major adjustment.

hope it helps
John
 
B

b0mbtrack

Petty Officer 1st Class
Joined
Mar 26, 2007
Messages
269
Re: idle rpm for merc 150

yeah i guess it would be best to go through the whole thing, i'm just used to the I/O's where it is just one screw you have to turn rather that going through steps and steps just to lower idle.
Thanks
 
j_martin

j_martin

Admiral
Joined
Sep 22, 2006
Messages
7,474
Re: idle rpm for merc 150

Once it's set up right, there is a one screw idle adjustment. The point is that if it is out of sync, that screw will have erratic results. All the adjustments cross affect each other. If the base line adjustment is set up right, then things behave as expected.

Even among the V6's there are several different combinations of specifications.

The idle speed screw is the one pointing aft at the bottom of the big timing control arm on the port side.

Do it once. It's a good education, and then you'll know you're not just adding to the problem when you adjust something.



hope it helps
John
 
You must log in or register to reply here.
Top