Nissan 8hp four stroke fuel problem

[Salty19]

I don't think it's fuel related unless it's vapor lock.  When fuel systems have problems (clogged jets, leaks, etc) they tend to prevent starting in the first place.

Could be a crack in the sparkplug or a bad coil or bad spark wire.

If the motor will restart after a squeeze on the bulb, it's probably either a leak in the fuel line or perhaps the filter is clogged.
If it will not restart unless waiting for another 10-20 minutes, it's probably the spark plug, spark plug wire or coil.  When these get hot, they expand and electrical contact is lost internally.

You can check this by taking off the spark plug, reattaching it to the wire, holding it onto a metal part of the engine (use tape to hold it, do NOT use your hand in the next step) then pull the starter and look for a spark.  In bright sun you may not see it, so do it in dim light. If it will not spark right after stalling (assuming engine is now hot) but will spark 10-20 minutes later once it's cooled, it's electrical.

Yep, I would try a new plug as they are cheap and a crack would certainly make it fail once hot.  Be sure it set the spark plug gap correctly, this is important.

[Wiggs]

I have been doing all the tests with ethanol free fuel. Although, up to this point I am afraid I have not, hope I have dodged a bullet there. I tried the easiest first and replaced the spark plug. Did not take it out but it ran for over an hour with no problem at the dock. Tomorrow will give it the acid test (first making sure my neighbor is home to mount a rescue if needed). I will be most pleased if this proves to be the solution. Thanks to all that have sent suggestions. I hope I do not need them, but they will be next if needed.

Thanks again to all, I will keep you posted.

Wiggs

[MacGyver]

 

Be sure to let me know Wiggs,

In my line of work (I work at West Access Marina on Carlyle Lake as the Mechanic, Fiberglass Tech, and Welder as my main job titles) I have found that 95 percent of the time, it is something small and easy.

I go back to work on Tuesday, so if needed I will look up your engine to see what all it might be as then I will know what all it has on it.
Some newer engines are a bit more finicky.........

Good luck, I hope that was the fix.

Mac

[philb Junkie19]

Wiggs,
I don't have a suggestion on your Nissan 's problems but learned somethings when I had chainsaw fuel problems a few weeks ago. Was running great.  Came back after lunch and nothing. Our local small engine mechanic told me about about the many problems he runs into with 10% ethanol gas which was no surprise. Said he could smell bad gas when he got the saw started. He recommended not keeping gas for more than a month as the alcohol in the fuel can easily absorbs water and it can separate out in the carb.  It can be hard to remove, in this particular brand of saw at least.  Buying fuel from stations with a higher turnover can help. He also points out that high octane can be worse than regular as it may stay in the ground longer with more chance of condensation.  The shop has something to measure the % of alcohol and finds the mix sold in stations sometimes contains more than the allowed 10%. He drives to an airport 20 miles away just to buy aviation gas. Sometimes gas will keep for a good long time. When it doesn't it can be a pain. Right now the only other small engine I need to keep running is the snow blower.
Phil

[Wiggs]

Sea trial complete, took the boat out to the harbor and back, about 50 minutes. Had one hiccup about 20 minutes in. My neighbor was looking for an excuse to take his boat out so he followed me all the way. Beautiful day, about 80 degrees, 10 mph wind. Too bad I did not have time to put the sails up. I will save that for tomorrow. I will not jinx it and call it a complete success (do not want to get too cocky) but we, and I do mean we (all those that offered suggestions) may have figured this one out.

Thanks, again to all,
Wiggs

[MacGyver]

One suggestion I do make to you Wiggs, is that you use Stabil with the engine.

Stabil is a derivitive of what mechanics used to use to clean carbs when they let them soak over night when doing rebuilds and such.

I use that in my older engines and newer engines that dont get run often (like once a week or less....

I use seafoam in my vehicles and such and Honda engines as Honda calls for it.

Glad it went well and hope it continues to do so.

Mac

[Wiggs]

Are you saying to use Stabil even if you are using ethanol free fuel? Simple enough to do if it will help. Maybe clean out the gunk I have deposited using ethanol?

Thanks again for all the help.
Wiggs

[MacGyver]

I use it no matter the fuel I use.

All fuels leave a byproduct as that is just a problem with combustion.

some additives will help to clean that up. Stabil is a good one. Sea foam is good but it doesnt do the same things as Stabil does.

Mac

[Wiggs]

Last question, I promise (well at least until my next problem). If using ethanol free fuel would you use the regular Stabil or the Marine formula (it says to use it when using ethanol fuel (marine)).

I will hang up and listen to your answer off the air.

Thanks,
Wigg

[MacGyver]

Id just use the regular stabil
I use the ethanol fuel with regular stabil

And actually......that marine stabil.......just Honda and Stabil working together to make a new product.....pretty funny that we havent needed it all these years.... and now Honda suddenly recommends the use of that now.......LOL
Being in the marine industry has its learning benefits.

Mac