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Need your opinion please,i never seen this happen!!!!

C

ciscokid

Regular Contributor
Hey guys I hope all is good!! I have a 1985 johnson 185. I rebuilt the carbs back in June,and it has been running great until this past weekend.I was full throttle 4300 rpms and all ofa sudden it started bogingdown real bad. took it home checked spark,compression,and all is good,so i pulled carbs and checked main jets.two top carbs are clean but the bottom carb has what looks like soot in it,like you would see on a piston.I have never had this happen before.ANY AND ALL INFO WELCOME.tHANKS AND HAVE A GREAT DAY!!!!
 
Blowback if in the carb throats.
No wonder if your WOT is only 4300.
Mainly caused by crank case combustions and may affect the reed valves.
Decarb your engine, get the WOT rpm up to min 5000, check your reed valves and check valves(recirc system) as they may be clogged up with carbon as well.
 
ciscokid said:
My manual says it should be running 4300 rpms,Thanks for the info.
Click to expand...
Might be as continuous cruising rpm, but not as max.
Cruising is normally max - minus 200. Your engine has the max power at about 5000.
If obtaining 5000, max cruising will be less than 4800.
Min max rpm is 4500, which gives min cruising rpm at 4300.
 
4300 RPM is nonsense !!!----------------Run to your local dealer equipped with a DYNOMOMETER and have the motor checked out as there is something really wrong if you can not get more then 4300 RPM-------Then again maybe your prop has too much pitch.
 
I was looking at this manual closer because it is old and faded,and its not the rite one.It was made somwhere else,because i go my new manual in the mail today and they are not alike at all.I compared the rpm range,and the old one where ever he got it says max 4300 rpm and my new one says 4700 to 5000.So i will burn that one!!Thanks for the Input!!
 
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