2.5L mercarb rebuild kit

[freak007]

The engine;

1984 2.5L/120 SN is 6784434 with Mercarb

The problem;

When slowly throttling up from idle it will sputter and die around 1500 RPM. If I go from idle (in gear) to WOT it would stumble around 1500 - 2000 and then pick up again. I have replaced the plugs (properly gapped), replaced the fuel filter, set the timing as well as checked the advance (8* @ 700 RPM in gear, 37* @ 1900 RPM). The points have been switched to electronic ignition by a previous owner. Due to the consistency of the flat spot no matter how fast or slow I open the throttle, I believe a complete carb rebuild is in order...

The tag that is *supposed* to be on the carb is torn off... but stamped on the body is "13898490" and under that is "3Y03"


The questions;

1. Is this the correct carb for my engine? - after my outdrive escapade, it wouldn't surprise me if it isn't
   
   
   
2. If the answer to #1 is no:
   
   
   A) what parts (jets, accelerator pumps, arms etc) are needed to make this the right carb?
   
   B) can I replace it with a Rochester carb #1351-8480?​
   
   
   
3. If the answer to #1 is yes, what is the PN for the carb kit I need?

 

[freak007]

Re: 2.5L mercarb help

Re: 2.5L mercarb help

Well I found some of my answers...

1. Yes this is the correct carb for my engine. This carb was used on 120R engines with the SN range of 6255466 to 6853913 and 140R engines with the SN range of 6256955 to 6852269. It is a 32mm Mercarb with 1.45mm primary jet and .84 power valve


2. NA

3. Still unknown... I understand there is a updated needle valve as well as accelerator pump, so if someone can direct me to the proper parts it would be appreciated...

 

[freak007]

Re: 2.5L mercarb help

Re: 2.5L mercarb help

ok, I have done alot of searching... I have found that Mercruiser has issued a Service Bulletin for this carb... and raising the float level is supposed to fix the stumble... but I still don't know what rebuild kit I need... please help

 

[watermellonI]

Re: 2.5L mercarb rebuild kit

Hey 007
you should be able to find that kit here on iboats, the main difference i found when rebuilding mine was the fuel plunger, some have a 90 degree bend in the shaft and some are strait, I think sierra made a kit that was designed to cover both types. Sierra also makes jets that could net ya alittle more power outta that motor if I m not mistaken but you need to do little more research on that before ya order.

 

[pferreira]

Re: 2.5L mercarb rebuild kit

wow,

You are having the same problem, with the same motor/carb as me!

I found this: http://www.sterndrives.com/precisionparts/300.html

I also found that Napa also has the kit you and I need and it's part 18-7097 and comes with all gaskets needles, etc.

I also do have the acelaration problem and was also told about the float thing. Can you tell me any more about the float adjustment?

I did open my carb after checking all filters, lines, but it all seems clean and functioning good.

So now I'll mess with the float.

Peter