Older Nissan 50 / 2cyl-2stroke, will not start.

[jhebbel]

I have a 16' bass boat with a older model Nissan 50 (2stroke / 2cyl), that ran ok until one day it started to cut out under low power (not stop completely), then when we opened up the throttle it died all together and we where unable to restart. When i got the boat back home i hooked up my hose and was still unable to start the engine, it apparently had no spark or no combustion as the electric starter worked fine but i could not hear any cylinders firing off. My first step was to check spark plugs, upon removing the plugs there was a thick coat of burned in oil. I suspect the previous owner (i just bought this boat a week ago) was not using the correct 2 stroke/gas mixture so i replaced the plugs, not necessary but i figured might as well, and removed the carb cover to clean the oil from the carb only to find a completely clean carb!?! Ive since tried to restart the engine and now get a backfire and that's it, still no combustion. any suggestions / ideas?

 

[JB]

Re: Older Nissan 50 / 2cyl-2stroke, will not start.

Could have slipped timing, jhebbel.

Go to the Engine FAQs and do "Outboard won't start". Let us know what you find.

 

[TOHATSU GURU]

Re: Older Nissan 50 / 2cyl-2stroke, will not start.

Thre are only three things that can cause a backfire on that model:

Trigger coil

Flywheel key

Reed issue

 

[chevyjet]

Re: Older Nissan 50 / 2cyl-2stroke, will not start.

Check to see if you have a good blue spark and if you do, the pull the carbs and look at the reeds, one might be chiped or broken, have a good look at the stop switch too cause they go bad often, see if you can disconect it and try starting.

 

[TOHATSU GURU]

Re: Older Nissan 50 / 2cyl-2stroke, will not start.

A bad stop button won't cause a backfire. Also, stop switches and kill switches don't fail very often. They are a simple, extremely reliabile, dumb, 2 wire switch. I have seen some fail, but it would be the last thing to look at in the ignition system check list.

 

[chevyjet]

Re: Older Nissan 50 / 2cyl-2stroke, will not start.

Any kind of intermitent short in your igition system can cause a small backfire/ pop and the stop switch is always a good place to start before you spend a bunch of time and money

 

[TOHATSU GURU]

Re: Older Nissan 50 / 2cyl-2stroke, will not start.

Actually you really are out of your depth....A backfire refers to a specific type of event that will not occur due to any possible problem with a kill switch as it can only go to ground or not.

 

[whitewater90]

Re: Older Nissan 50 / 2cyl-2stroke, will not start.

Could be the CDI box, have had them fail and fire way out of time causing A backfire.