Hey guys! After fighting with my grandpas old boat for probably about 3 weekends I finally got it running pretty nicely and I just have a question about carbs.
It’s a 1984 mercruiser 140 and I was originally having a problem with it shaking horribly at idle and spiting through the carb. so I replaced points and condenser, wires cleaned the distributor cap and it didn’t help… cleaned the carb and adjusted float like 14 times and thought it was running rich (would only idle with mixture screw all the way in). Was cold fouling the plugs and I didn’t want to put a new set in until I found the reason, so I bought a cast Chinese carb and swapped the jets. Still ran awful and still spit. Finally yanked the number 1 wire out of the distributor with it running terribly and nothing changed… plugs are bad (duh— back to basics) ended up checking the plug resistance and two of the resistors in two plugs were open. swapped new plugs in and it ran like a top! Nice smooth idle, the mixture screw responds, no more spitting through the carb…
Anyways I wanted to swap back to the oem carb because I’m a huge believer that oem parts are superior and I noticed it still runs good but I really have to put quite a bit of pressure on the throttle linkage of the original mercarb to get the idle back down… also the mixture screw responds because I can hear the mix get lean and fat when I adjust it but it won’t kill the engine when all the way in. The Chinese carb will. when I had it apart I noticed there’s no lateral play in the throttle linkage but quite a bit of axial play. The Chinese carb does not have this much play. Could this play be the reason the boat runs better with the Chinese carb? And if so.. how do you solve excessive axial play in the throttle shaft?
It’s a 1984 mercruiser 140 and I was originally having a problem with it shaking horribly at idle and spiting through the carb. so I replaced points and condenser, wires cleaned the distributor cap and it didn’t help… cleaned the carb and adjusted float like 14 times and thought it was running rich (would only idle with mixture screw all the way in). Was cold fouling the plugs and I didn’t want to put a new set in until I found the reason, so I bought a cast Chinese carb and swapped the jets. Still ran awful and still spit. Finally yanked the number 1 wire out of the distributor with it running terribly and nothing changed… plugs are bad (duh— back to basics) ended up checking the plug resistance and two of the resistors in two plugs were open. swapped new plugs in and it ran like a top! Nice smooth idle, the mixture screw responds, no more spitting through the carb…
Anyways I wanted to swap back to the oem carb because I’m a huge believer that oem parts are superior and I noticed it still runs good but I really have to put quite a bit of pressure on the throttle linkage of the original mercarb to get the idle back down… also the mixture screw responds because I can hear the mix get lean and fat when I adjust it but it won’t kill the engine when all the way in. The Chinese carb will. when I had it apart I noticed there’s no lateral play in the throttle linkage but quite a bit of axial play. The Chinese carb does not have this much play. Could this play be the reason the boat runs better with the Chinese carb? And if so.. how do you solve excessive axial play in the throttle shaft?