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1973 Johnson 65hp excessive smoke, loads up at idle

GreenbackChaser

New member
Hi, I have a '73 65hp Johnson. Starts up no matter what, but smoke is terrible, and seems like it floods out at idle. I have to start up, rev the motor, let it warm up and clean out, then go right away. If I stop to idle, more than 2 or 3 minutes, it loads up again, and i have to repeat process. I was a mechanic on forklifts, and suspect either bad float setting or idle mixture. Am I on the right track here ? I've been told that newer ethanol, non leaded gas can hurt the Reed valves. I believe setting carbs should fix the problem. Any suggestions an where to find parts ? Walleye season is coming fast, and I spend every hour on the river. Thanks
 
Is the thermo switch choke in service , yes , no or do not know ?---Possibly a float valve leaking and flooding one cylinder.-----Post results of a compression test here.---Reed valves are NOT bothered by non leaded fuel.----Not sure why anyone would think that !!---Carburetors do not have an idle mixture screw !---Check fuel pump diaphragm for a pin hole.----Check cooling system for missing thermostat or stuck open poppit valves.----Should not be hard to find the culprit here.
 
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Thank you. I kind of pushed thru end of last season, just bought boat in March. As soon as weather allows, hopefully next week or so, I'm in Chicago, I'll check what you suggested. I kill every mosquito within 2 blocks, when I start it. Kind of embarrassing tho. I'm not sure about the choke. It has a toggle switch, electric choke, on the controls. I did make sure the manual choke was in correct position. Many thanks, and happy new year. Open water on the Winnebago system can't come soon enough. I'll post on here, once I go over everything. Hopefully help someone else in the future. For now, I'm stuck with the oldie, but she runs. Gets me on the water. Thanks again.
 
With manual choke in the " correct " position what happens when the key is turned to " on " or the run position ?-----Does choke come on halfway , yes or no ?----When toggle switch is operated does choke go on all the way , yes or no ?-----And what happens if the motor starts and you push manual choke control to off ?
 
With manual in auto, choke is off, goes full choke, when I hit the momentary toggle, then back to off. Seems like it's working as it should. Manual choke on motor has on/auto/off, I believe in that order. Motor just seems to burn a lot of has, and loads up when started or at idle.
 
I am not there to see, but it sounds like the thermo-electric choke function has been by-passed.----I am quite familiar with how that motor left the factory.----No telling what you have today.----Do yourself a favour and post the compression values on it.
 
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I'll take compression when I have a chance to work on it, let you know. I've been wanting to check it, just was so happy to finally be on the water again, I didnt do much on it, other than making sure water pump, cleaning n living entire motor.before this season starts, I have a lot to go over. As way it looks now, I'll have all spring and fall, on the river. Have to make sure everything is reliable, can handle 18 hour days. As for the electric choke, that is functioning perfect. When I get a chance, I'll let you all know what I find. I used to rebuild engines and transmission s all the time, but i never did a 2 stroke. Being a '73, i shouldn't have any problems.
Thanks for the help.
 
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