1980 johnson 70hp accel issue

[17rogue70]

hi all,this is an excellent site .very informative from all that ive seen thus far.i recently purchased a 1999 rogue flats boat with a 1980 70 hp johnson with 150 psi in all cylinders.and with that being said my issue is this,i go through warm up procedure and try to plane out at take off but engine stalls out. what i can do is re start engine raise to high idle and close choke to almost stalling out.lower idle place into gear and then take off under full power. if i let the engine idle while retrieving trlr to load up ,the engine seems to load up and stall while trying to put boat on the trailer.meaning i have to go through clearing process all over again.any and all help is greatly appreciated in advance. thanks ,mike

 

[kenmyfam]

Re: 1980 johnson 70hp accel issue

Basic health check will go a long way.
Compression (you have done already)
Spark
Fuel delivery
Spark plug condition.

If I was to take a "best guess" I would rebuild / clean the carbs and make sure you do not have ethanol poisoning. Remember this is just a guess.

Check this link

http://forums.iboats.com/showthread.php?t=330129

Welcome to iboats

 

[mikesea]

Re: 1980 johnson 70hp accel issue

sounds like your idle jets may be dirty,best fix is total dissassembly and soking in carb cleaner,blow out with compressed air,if your fairly handy ,can use a screwdriver and open end wrench ,you likely can do it yourself,no springs or balls to fly apart,just give yourself a good place to lay out the parts ,remove all plastic and rubber from carbs before placing in cleaner ,which can be purchased at autozone or he like

 

[ClassyGlassy]

Re: 1980 johnson 70hp accel issue

don't soak in carb cleaner.....it can leave a tarnish! soak them in sea foam....

 

[17rogue70]

Re: 1980 johnson 70hp accel issue

forgot to add fuel delivery was new and clean .as suggested low idle jets were dirty.spark was good but the previous owner had 1 champ plug and 2 ngk plugs.why do people have to be so cheap as to do this kind of mech work?glad to report all is well,thank you guys so much for all replies.this place is the "BOMB" now i just cant seem to find my alarm buzzer.ignition is seperate from the controls.tried unplugging the sensor to no buzz at all.and no wires coming out of the bottom of the bottom the shift/throttle contols..these are the controls without the high idle lever. thanks again for all replies and answers.

 

[willamettejeff]

Re: 1980 johnson 70hp accel issue

now i just cant seem to find my alarm buzzer.ignition is seperate from the controls.tried unplugging the sensor to no buzz at all.and no wires coming out of the bottom of the bottom the shift/throttle contols..these are the controls without the high idle lever. thanks again for all replies and answers.

Need to ground the sensor wire with ignition key on to activate the high temp alarm if it is working.