I have a Johnson ?

[whoitd]

Hello boaters\marine techs, I was wondering if a 1975 mid section will work with a 1977 power head? Just wondering if this is the reason for my multiple nightmare problems with engine performance.Oops forgot working with Johnson 70hp.

 

[jim_in_day]

Re: I have a Johnson ?

I believe that the 75-78 midsection part numbers are the same, i put a 75 midsection/lu on my 76 Rude 70hp. What kind of problems are you having? The 3 cyl link and sync procedure is confusing and getting it right is very important in making that engine work properly

 

[whoitd]

Re: I have a Johnson ?

That is the problem that I am having trying to sync.I do what the manul says to do, but once I put in gear it stalls. The manual said to use timing light turn idle til tdc . I have idle set to 1000 to 1100 rpms and it is around 750 to 800 in gear, with in 30- 40 sec stalls right out. The sync rod is adjusted to 126mm as per what the manual said to do.<br />Anyone have any more ideas what to do??? Thanks, Jim

 

[jim_in_day]

Re: I have a Johnson ?

Sorry I didn't get back, been moving. The link and sync procedure in the manual confused the he### out of me, I ended up turning the idle screw until I got TDC, Then i shut off the engine, removed the cam adjuster and adjusted it until it just picked up the carbs, restarted the motor, and backed off the idle screw to the correct idle (about 1050 on muffs). Also make sure that all 3 carbs are in sync. We use alligator clips with straighted paperclips attached to the throttle linkage on each carb and make sure that all 3 move simultaneously.