Carb help

**Justplayin** · 08-15-2016, 10:50 PM

I am new to this site but and looking for some help! Have a decent motor and wondering if I am crazy or is my bottom carb missing the what I call pumper/plunger rod and linkage? As far as I can tell I have a 91 2.5l mariner, freeze plug serial "D079539" any help would be amazing thank you!

**1nebel0** · 08-16-2016, 12:28 AM

Looks to be missing to me as well.......

**Dave Strong** · 08-16-2016, 12:35 AM

It's gone but alot of those carbs the pumps did not function. My 245 HP 2.5 had all the linkage but no passages to make them pump. Not sure on your motor but could also be the case. As far as I know the only pumps that worked were on the carb F1 motors. The reason for the pump was to get rid of a bog coming out of a 3g corner.

Dave

**tlwjkw** · 08-16-2016, 05:18 AM

only tha very first wmh pumpers actually pumped... even on tha production motors...some worked as intended, depending on who ya talked to, but most were a pia... first 245 i had came with 'em.. stripped tha guts and epoxied tha castings on those.. looks like thats what ya have there.. best i remember they were only functional for first year, maybe two, production and/or hi perf... tha next batch had tha casting's for tha pump but no hardware (guts)... next had no clue they were ever part of tha thing.. easiest thing would be ta remove tha little linkage and plungers on other two... as long as there is not any diaphragm leakage they will be jus fine...

**hydroplay** · 08-16-2016, 07:12 AM

The accelerator pumps were so the low speed/idle circuit could be leaned out more for several reasons but a richer mixture was needed for smooth acceleration- hence a squirt of fuel when the throttle was advanced. That gave a quick richer mixture until the main circuit responded. Owners may not have liked that approach but the EPA did. Since you have 4 cylinders working as intended, the temporary lean spot in 2 may not be much of an issue. But if it is , you can easily repair it back to original. Or eliminate all the pumps, block the passage from them and richen up the low speed circuit and you will like it even more.

**Justplayin** · 08-16-2016, 07:41 AM

WOW and thats why I asked, you guys are awesome! I love the motor but it deos sputter until it gets wraped up, I will try and get the parts to replace it for the rest of the season and try to plug and richen it up this winter! Thank ya'll very much, now the search for parts!

**Justplayin** · 08-16-2016, 07:56 AM

Does anyone have a link to parts page and or the blocking off procedure for the pumps! Thanks

**hydroplay** · 08-19-2016, 07:28 AM

The accelerator pump carbs were used on the early SST-120 race motors so we were subject to some inspection to make sure things remained stock. That meant we couldn't blatantly change the exterior appearance to let an inspector get suspicious. The passage I plugged was from the vertical passage in the front center of the float bowl cover into the main carb body. I did that by cutting a new float bowl gasket that covered that hole. Since you are not constrained about stock inspection, you can trace that passage back to the pump chamber and just put a drop of epoxy there to seal it off. I had experience with smaller Merc carbs that used a similar pump to prime the motor for starting that would allow the circuit to siphon fuel if the check ball didn't seat. I don't have a V-6 carb to see if that is a possibility so maybe the plugging is unnecessary once you de-activate the accelerator pumps. You will have to enlarge the smaller low-speeds jets as well to get things to work right.