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1982 mercrusier inline 4 140 bogging out at full throttle and not able to rev above 1000 rpm's

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Raycer55

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Ok so im all out of ideas and need help so i have a 1982 mercrusier 3.0l I4 and it ran great at idle but when you got to full speed it would bog down and die. Now it wont even let me rev it above 1000 rpm's or it would die out and not want to restart. I have replaced the coil,alternator,electric ignition,plugs,plug wires,cap,rotor and all the oils changed but when i pulled it out and opened the lower unit drains the oil coming out looked greenish brown colored and im wondering what that means. Also if you rev it up to 1500 rpm's in throttle only it make a grinding sound and im suspecting something in the outdrive is going bad. Will something like that cause it to not run right? I really need help im almost ready to try and sell it and get something different.
 
Raycer55 said:
Ok so im all out of ideas and need help so i have a 1982 mercrusier 3.0l I4 and it ran great at idle but when you got to full speed it would bog down and die. Now it wont even let me rev it above 1000 rpm's or it would die out and not want to restart. I have replaced the coil,alternator,electric ignition,plugs,plug wires,cap,rotor and all the oils changed but when i pulled it out and opened the lower unit drains the oil coming out looked greenish brown colored and im wondering what that means. Also if you rev it up to 1500 rpm's in throttle only it make a grinding sound and im suspecting something in the outdrive is going bad. Will something like that cause it to not run right? I really need help im almost ready to try and sell it and get something different.
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Sounds like fuel delivery to me. When is the last time you gave the carb a good cleaning? About the outdrive, may have a little water in the oil. Recommend you clean carb, change outdrive oil. Not sure what to tell you about the noise....one of the outdrive experts will probably respond.
 
Fastatv said:
Sounds like fuel delivery to me. When is the last time you gave the carb a good cleaning? About the outdrive, may have a little water in the oil. Recommend you clean carb, change outdrive oil. Not sure what to tell you about the noise....one of the outdrive experts will probably respond.
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alright do you think maybe thefuel pump could be bad? The crab was rebuilt a little bit ago but im going to clean it and what kind of gear lube do you recomend for this. We used something we thought was right but idk and im guessing maybe the gimbal is going bad idk yet tho. Thanks for the response
 
Raycer55 said:
So i found the problem it was the seat for the needle some how came loose and was not letting the carb fill up with gas.
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Thats great! I use the Mercruiser out drive gear lube. Costs a little more but I change it only once per year so cost is really minimum. Not sure what to recommend on the grinding outdrive noise. If its actually grinding ( noise describing is difficult ), I wouldn't think it would be safe to operate. Again, maybe one of the experts will jump in here on the outdrive issue.
 
Well we put it in gear a few times and it had no noise so idk it may have been something engine related to running bad but it's better now just need to tune the air to fuel and the fuel amount because it stutters at start now from us messing with it trying to get it more fuel
 
Raycer55 said:
Well we put it in gear a few times and it had no noise so idk it may have been something engine related to running bad but it's better now just need to tune the air to fuel and the fuel amount because it stutters at start now from us messing with it trying to get it more fuel
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If its a Mercarb and had the power valve actuator in the air horn ( top portion of carb ), care has to be used when placing the horn back on the carb body or the actuator may not be contacting the power valve. This would cause a bog when accelerating...slightly lean condition. Anyway, adjust the air/fuel screw ( s ) for highest idle, then readjust your idle RPM. The idle RPM is supposed to be adjusted with boat in the water due to exhaust back pressure. Hope all of this helps you. Good luck!
 
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