1999 50hp Johnson only starts at full throttle

[Lucaswt]

Need help, I have a 50hp johnson outboard that only starts at full throttle, as soon as I bring the handle down a bit, it bogs down. It wont start at neutral. I cleaned carbs, new gas/oil, etc. Dont know what else to do. If you guys could help I would really appreciate it.

 

[racerone]

Model # is ?----How did it run for you last season ?-----Need to post compression numbers.-----Does spark jump a gap of 3/8" or more ?-----Check flywheel key.-----Pushing key in and holding it in while cranking it over ?

 

[Lucaswt]

a month ago it was running "fine". it would idle for 5 minutes and then bog down, but it would start fine. I dont know model number, serial number is faded out. I replaced spark plugs too.

 

[Lucaswt]

Primer solenoid leaking gas after key is pushed in. Could that be the problem?

 

[racerone]

A simple repair kit is available for the electric primer valve.------Answers to questions will help you.

 

[Lucaswt]

I’m trying to get the repair kit but all reviews say that red valve from Sierra does not fit right! I apologize I am not a mechanic I changed the plugs, compression is good on both and I push the key in and crank it, it won’t start and I see gas leaking from red valve. Been on Amazon and on the internet but I cannot find a repair kit for a 50hp johnson 1999 that is not from sierra. Need help

 

[racerone]

Try-----evinrudeparts.ca-----A shop that knows motors.------Amazon has no mechanics.

 

[Lucaswt]

Got the repair kit for the primer solenoid. Replaced it. Not leaking this time. Got a new ignition key switch. Old was damaged. Tried to start it! Nothing. It will crank but will not fire. Only will fire/start at 3/4 of open throttle. Please help!

 

[oldboat1]

Are you advancing the timing plate while throttling up, or just operating the carb?

 

[Lucaswt]

Are you advancing the timing plate while throttling up, or just operating the carb?

No.

 

[oldboat1]

That is, the throttle plate should turn when twisting the tiller handle. Carb should open as well without manually operating the roller.

 

[Lucaswt]

Re do carbs and found out square plastic cover on top of carb was cracked. Replaced it with a new one and now starts with muffs on driveway. took it to the river, it did start but then dies. Somebody told me that I need to adjust the idle but I dont know which one is it?

 

[racerone]

Time to post the compression values.----In this case do a spark test , both plugs out to see if spark will jump a gap of 3/8" or more.----Then install plugs and see if it will still jump that gap.----As stated before if you answer the simple questions , folks here can point you in the right direction !

 

[Lucaswt]

I will check compression and also the spark plugs and I will post numbers. I forgot to mention before when It did Start I was able to move the Throttle Do gear and it idle for five minutes and then it died again. The next time it did start again and I just moved the throttle up and it ran fine. Top speed 25mph. Back to neutral and it dies.

 

[Lucaswt]

II was able to do a compression test. Top cylinder 140, bottom cylinder 130. I was not able to do spark plug test, but I did it manually. I am getting a spark. Also I learnt that I was not using the right spark plug (QL78YC), I already order them. We will see if that makes a difference.

 

[oldboat1]

Can't confirm offhand that is the right plug, but use a .030 gap (not to be confused with testing gap discussed above). Fellow lister Vic is one of the plug gurus, and may chime in.