1973 Johnson 65 HP running isues

[Nitrobuzzard]

I've got to say first I'm soooooo glad I found this site!! Now for the motor problem, like the topic says, its a '73 model 65 horse 3-cylinder motor. Boat sat for about 2 years, first thing I did was change the plugs and cleaned carbs. Runs good but while its running at WOT in the lake but you can feel it trying to "kick" in, feels like something is holding it back. I've checked the fire while it was running by pulling the wires one at a time, 2 were more noticable in the RPM drop but they all dropped the RPM's. Any help? Thanks in advance!!

 

[Bass Runner]

Re: 1973 Johnson 65 HP running isues

Sounds like a fuel problem, try decarb first if that dosn't do it, either you have a small hole in a gas line or it is trying to plug up, or it could be a weak fuel pump. Just my thoughts i have a 1974 70hp basicly the same motor. By the way welcome to Iboats, if you have a problem and it can't be solved here you are in deep dookie.

 

[backdraft]

Re: 1973 Johnson 65 HP running isues

Weak spark on one cylinder or a lean mixure on that same cylinder. Close the spark gap down a little , to about 25 thou, on that cylinder to see if that helps , just to start.

 

[Nitrobuzzard]

Re: 1973 Johnson 65 HP running isues

Today I bought new float valves and seats, found 1 that was stuck closed and another semi-stuck (if that's possible LOL) I'll have to try it out tomorrow afternoon and see what happens. I've re-placed all fuel line and the nylon "T", also have checked the pump, seems to be pumping real good at cranking RPM............I'll post back after I take it out.....thanks for the input, keep it coming!! <br /><br />Nitrobuzzard

 

[Nitrobuzzard]

Re: 1973 Johnson 65 HP running isues

oh yeh, thanks for the welcome Bass Runner

 

[Nitrobuzzard]

Re: 1973 Johnson 65 HP running isues

ok, here's the deal.........the float valves did help out, quite a bit actually. It's still not running at the best performance it can and you can still feel the "surge" every now and then. I can be cruising along around 35mph, not touching the throttle, and feel it "kick-in" for just a second and then it quits. I've checked the fire to the plugs with a home-made contraption that allows me to see the spark as it fires. It's jumping a good 1/4" to the plug tip and it is consistent. I've changed the plugs as well. When I pull #2 wire off the engine dies but with #1 and #3, it just drops the RPMs.........After I run it for a bit, water hose hooked to it in my driveway, I can pull the plugs out and they are wet, very wet. Is there any way for water to get into the cylinders? I know on a car engine if its got a blown head gasket it will but not sure about outboards. Thanks for ALL your input and help. Sorry for the long post just trying to give as much info as possible.........

 

[Bass Runner]

Re: 1973 Johnson 65 HP running isues

Are the plugs running wet or dry, it could be coils breaking down at high rpm, or you might try checking sync and link, did you decarb the motor it could be gummed up reeds. Oh by the way you are welcome

 

[Nitrobuzzard]

Re: 1973 Johnson 65 HP running isues

I can let it sit at idle and the plugs will be wet. I think I found the problem though. I think someone has put the wrong plugs in it. The OEM plug is a L77JC4 Champion,(so I was told) I cross-referenced them to an NGK plug and will try those out this evening. I have cleaned the carbs, took them off and opened every hole in them with the exception of the "caps". Soaked them with carb cleaner and blew them out with the airhose. Maybe having the right plugs will fix it...I'l post back. Thanks for the help Bass Runner

 

[Nitrobuzzard]

Re: 1973 Johnson 65 HP running isues

Well, the plugs fixed it!! I guess the resistor in the plugs were to much. Put the NGK's in there and it runs like a new one.........THANKS TO ALL for your help!!