1974 johnson 70 hp stall at idle/in gear

[WINDGAGE]

Hi, ive got a 3 cylinder 1974 70hp el/start johnson and its giving me grief when at idle and starting off, as it just dies and leave me blowing around the harbour, which can be funny but a bit shameful.<br />It will only start by usuing the manual choke and fast idle leaver on full, then does,nt idle most of the time and cuts out soon as you put it in gear even on the return journey with the engine warm. It goes like the clappers when the revs are up and your in motion, any thoughts<br />regards Windgage

 

[blueboat1]

Re: 1974 johnson 70 hp stall at idle/in gear

I have the same motor. I just got it 5 months ago and it would not idle. to start it i have to use the choke each time. I ended up replacing all fuel lines to carbs, carb gaskets, and head gasket (your prob isnt bad but mine was). Now it idle fine but i still have to use the choke to start it. The more i use it the better it seems to run. If your sat a long time it may just need to be de-carboned the engine, check to make sure carbs are tight and change fuel lines from the tank all the way to the carbs. Cheap things to check so you cant go wrong. good luck

 

[Cricket Too]

Re: 1974 johnson 70 hp stall at idle/in gear

Windgage....If I were you I would get the manual for this motor, rebuild the carbs and then adjust the idle according to the procedure in the manual.

 

[WINDGAGE]

Re: 1974 johnson 70 hp stall at idle/in gear

Thanks to all for the snippets of info, i have ordered the manual and shall strip the carbs and <br />clean and adjust as necessary,<br /><br />regards<br />windgage.<br />England.

 

[blueboat1]

Re: 1974 johnson 70 hp stall at idle/in gear

Only adjustments you can make to the carbs are idle speed and sync (make sure all go when told to go and butterfly all flapping wings together) <br />Good luck and keep me posted if you find a way to get it to fire up without the choke.<br />Thanks<br />Scott

 

[The Marine Doctor]

Re: 1974 johnson 70 hp stall at idle/in gear

If you have to use the choke all the time to start the engine...even after its warm...the problem will lie with the low speed jets. They will not be delivering enough fuel to start. If possible adjust them...or oversize them.<br /><br />TMD