my nissan won't stay running...

[cklamp]

Forgive me if this is a somewhat faq, but I did a few searches, and didn't hit the nail on the head for my problem exactly. or have tried a few of the suggestions i've seen already.

I have an NSF3.5 that will start in the "start" position, but won't actually stay running. I bought it used, and it worked fine at the time, but i've done everything in the manual to get it to "run" but it just won't stay running.

I've never put it on the wrong side, but i did change out the Spark Plug just in case. It does appear somewhat "oily" as if it was on the wrong side at some point in it's life.

What happens in the "start" position is I can pull the cord, and it will fire up... run for about 15-30 seconds. Start sputtering, and slowing down... then there is a little "puff" of smoke that comes out the carb.

Ideas?

Thanks
Christian

 

[TOHATSU GURU]

Re: my nissan won't stay running...

Tak it into a dealer and have it fixed or start troubleshooting. Chances are it's a dirty carburetor.

 

[cklamp]

Re: my nissan won't stay running...

I'm unemployed so taking it into a dealer isn't the best option right now.

As i said, i'm pretty mechanically inclined, and I do have the factory manual. I did tear the carb apart, and rebuilt it, and it seems a little "better" but that's a very subjective term. It still won't stay running but the "backfire" out the flame arrester isn't nearly as much, and the smoke I saw coming out of the shaft isn't as much anymore either.

I was going to attempt to check the timing, but unfortunately it won't run long enough to do that. The timing light is going off, just won't stay running long enough for me to line up and check where i'm at.

I was also going to check compression, but my compression tester doesn't have the right threading, so will have to try that later.

I did notice the spark plug seems to have a lot of oil on it. Is that normal for a 4 stroke?

Later
C

 

[TOHATSU GURU]

Re: my nissan won't stay running...

I would go back to the carburetor again and clean it one more time. The plug shouldn't have any oil on it. It's pointless to check the timing, but you might want to make sure the flywheel key isn't broken. Did the warranty just run out on this engine?

 

[cklamp]

Re: my nissan won't stay running...

What would oil on the plug be indicative of? I cleaned off the plug and put it back in. tried to start it, and it get's oily again almost immediatedly.

While I had the carb off, I did replace the oil, and pulled the gas that was in the tank as well.

I can easily pull the carb and clean it again... it was much easier than I expected.

I bought the engine used. I think i'm the third owner, so no idea about warranty status.

later
C

 

[pvanv]

Re: my nissan won't stay running...

Warranty is 3 years on these.

Oil on the plug would be either overfilled oil, laid on wrong side, or bad rings. In your case, it might be semi-unburned fuel, as opposed to oil.

The "puff and stall" thing is usually a sheared flywheel key, throwing the timing WAY off. That can leave a wet plug.

 

[mmccoy555]

Re: my nissan won't stay running...

Very rarely will you have a major problem with that motor. I'm sure there is something in the carb or just an adjustment. oil on the plug would indicate to me that it's running lean. Is the needle valve back in to proper spec.?

 

[Yetii88]

Re: my nissan won't stay running...

Is the fuel your using mixed with 2 stroke oil?

 

[cklamp]

Re: my nissan won't stay running...

I was going to check compression to see if the rings are bad, but my tester won't fit the tiny little spark plug, and not sure I want to buy that part just to test for this.

No, i'm not using mixed gas. It's standard, but it does have that damn ethanol that the manual warns you about. Every station near me uses that stuff in their gas. Could that be the issue? anything I can do to fix that?

Oil level is correct, I just swapped it, and have verified a couple times it looks good.

I've also had it on a Motor Stand, or a Motor bucket for at least the past 3-4 days, and before that it was correctly laid down on the right side for 3-4 days, so the oil should be in the right place.

Needle valve and float valve = same thing? If so, yes it is put back in correctly. I followed the factory manual to a T, and checked the measurements with a set of calipres.

I do have a call into one outboard repair place as I'm not sure I want to dig far enough in to check that flywheel key out

later
C

 

[pvanv]

Re: my nissan won't stay running...

No, ethanol will not leave oil on the plug. Yes, the needle is what is activated by the float. Sounds it's like time for a Tohatsu mechanic to have a look at it.

 

[cklamp]

Re: my nissan won't stay running...

That's what I did today. I talked with two places. One guy didn't think the sheared flywheel key would be the issue. He felt it shouldn't even start up it would be thrown off so badly. That guy was recommended by a few local people but he was going out of town for a week.

Another place I called, that I took it to, did think the flywheel key could be the issue, but as expected, said they couldn't be sure till they got it into the shop and took a look at things.

They normally charge 90$ an hour... i'm hoping i'll know what the issue is sooner than later. I do hate that I didn't figure it out myself, but lack of the special tools sucks.

later
C

 

[cklamp]

Re: my nissan won't stay running...

ugh, what fun... the shop is still working on it. The carb was dirty, but that wasn't the only problem. They've rebuilt the carb, and it still has a lot of the same symptoms but not identical.

They now suspect there is a vacuum leak somewhere as well. As it revs up and down at times when it shouldn't be.

what a pita...

later
C

 

[pvanv]

Re: my nissan won't stay running...

There aren't but 2 places a vacuum leak could occur -- intake manifold gasket, or carb base spacer (and 2 gaskets) -- unless you have a crecked intake or some other such peculiar problem. So it's doubtful that there's a real vacuum leak.

Have them revisit the carb. A good soaking, not just a blow-out with spray stuff. I have had to replace one of these carbs as defective -- but that was under the 3-yr. warranty.

 

[cklamp]

Re: my nissan won't stay running...

This is really frustrating. They called me saying it was ready, so I go to pick it up, bring it home, and it's doing the same thing it was initially, but with a new bonus.

Starts up, runs for 45 seconds, then dies with a puff of smoke coming out of the flame arrester. only NOW, there is gas coming out of the flame arrester too. It's all over the side of the engine now. Totally awesome!

They've cleaned the carb, installed a new carb kit, and a new spark plug.

Later
C

 

[TOHATSU GURU]

Re: my nissan won't stay running...

Problem 1) It's the carburetor...No fuel pump on it so the problem with the fuel overflow has to be something in the carb.

Problem 2) It's possible, that in addition to carb issue, you have something else wrong. It may be as simple as the engine being on an incorrect tilt pin position(can't draw fuel through gravity) or it may be an ignition component.

 

[cklamp]

Re: my nissan won't stay running...

good advice... it's back at the shop and they are supposed to be looking at it again tonight/tomorrow. I thought they knew a lot about tohatsu's but i'm getting the impression the mechanic there doesn't

What ignition component could be going bad? I've suspected that earlier myself due to the fact it will start up and do the 45 second run after sitting for a while. As if something was cooling down.

later
C

 

[TOHATSU GURU]

Re: my nissan won't stay running...

The ignitor may be the culprit. The service manual has the test values in it so the dealer shouldn't have any problem checking it.