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timangiel 10-01-2012 01:22 PM

Nissan 9.8 priming problem
 
I have a Nissan 9.8 outboard that I bought new earlier this season. The other day when we were preparing to go out for a sail, I started pumping the primer bulb and it seemed like it wasn't firming up like it normally does, and it appeared that some fuel actually was dripping from the rear side of the engine near where a stream of water exits when the motor is running. It made a rainbow slick in the water, so I stopped pumping. The engine was difficult to start, but it did start, and once it started it seemed to run fine. We went out for a day sail and when we came back in it started right up and ran fine. Has this ever happened to anyone else? Anyone know what is happening? I always disconnect the fuel line and let the motor run until it runs out of gas and dies when I return to the dock.

RichH 10-01-2012 03:37 PM

Re: Nissan 9.8 priming problem
 
Probably some fine 'crud' got stuck on the needle valve that supplies the carburetor bowl --- does happen. Use only 'fresh' fuel and or properly stabilized fuel to prevent. If it continues, thoroughly clean out the tank, change the gas-line filter, etc. and start over with clean fuel, clean everything else, etc. Most times this is just a transitory 'glitch' as even 'very fine' particles stick together to make larger and larger particles.

I wouldnt go through the cost and trouble of fixing it, unless it starts to be a recurrent problem ... until then dont 'pump so hard' as it sometimes takes a wee bit of time for the 'soft rubber' tip of that needle valve to form a complete seal.
I usually dump a wee bit of carb cleaner into my fuel every now and then, always try to run the carb to 'dry' when shutting down ... and remove the jets to squirt in isopropyl alcohol to 'flush' and keep the 'jets' and air passages/bleeds from forming gum during long periods of layup.

Clean and 'fresh' fuel is the best and first consideration. Dump the 'old' gasoline into your auto and ancient lawnmower.

INMA 10-02-2012 01:53 PM

Re: Nissan 9.8 priming problem
 
Sounds like a fuel leak under the cowl.

When the fuel spills near the engine the vapor causes the intake to run rich making starting an issue.

Lift the cowl and the fresh air helps the engine start.

Check for a leak near a hose fitting under the cowl.

Nylon ties are not hose clamps, Tohatsu have a similar issue on their smaller outboards.

waltsn 10-02-2012 02:30 PM

Re: Nissan 9.8 priming problem
 
My Tohatsu 4 hp did about the same thing. I had left it sitting over the summer in a hot garage.

I went to use the outboard and the same thing happened as the OP, as I pumped, gas came out somewhere on the carb.

In my case, it turned out to be a stuck float that fixed itself once the gas was in the carb for a while.

Same outing, the outboard would not idle and this turned out to be the idle jet completely varnished over.

I had run the outboard dry but aparently whatever gas was left in the carb closed off the jet and froze the float. Im now adding all sorts of junk to the gas (like seafoam) but not sure it does anything.

Sumner10 10-02-2012 05:18 PM

Re: Nissan 9.8 priming problem
 
If you don't have one....

http://purplesagetradingpost.com/sum...nk%20Lines.jpg

...I'd think about a good filter/water separator like above. We have had good luck with it and the Tohatsu 9.8 HP. Always starts right up and we have only had to prime with the bulb the first start-up of a trip.

One thing about running the carb dry. I personally don't do that until the end of the trip if we are using the outboard every day or so and then also remove the float bowl drain screw. Drain the bowl completely and then put the screw back in. The screw is usually on the bottom or down low on the side of most carbs.

Running the outboard til the motor stops lowers the fuel level to the main jet. Then the engine dies, but there is still fuel in the bottom of the bowl that can get nasty if stored that way.

Here is info on the ...

http://purplesagetradingpost.com/sum...nk%20Lines.jpg

...filter that we used....

Macgregor 26S Outside Mods page 36

Good luck,

Sum

---------------------------------------------

Our 37 Endeavour --- Our 26 MacGregor --- Trips With Both

http://purplesagetradingpost.com/sum...avour-sm-1.jpg

waltsn 10-02-2012 05:26 PM

Re: Nissan 9.8 priming problem
 
Hello Sumner (walt here)..

That water separator isnít a bad idea but I donít believe Iíve ever heard of someone with an outboard / small tank having a problem caused by water in the gas.

The problems are always because of clogged jets or such and it because of how the gas evaporates. I understand that itís the additives in the gas that address this.

Iíd get a water separator if I thought it would address any problem Iíve ever had or heard of but it seems to me that it has nothing to do with either the OP's problem of the problem I had in the previous post.

Am I missing something?

Sumner10 10-02-2012 05:50 PM

Re: Nissan 9.8 priming problem
 
Quote:

Originally Posted by waltsn (Post 928939)
Hello Sumner (walt here)..

That water separator isn’t a bad idea but I don’t believe I’ve ever heard of someone with an outboard / small tank having a problem caused by water in the gas.

The problems are always because of clogged jets or such and it because of how the gas evaporates. I understand that it’s the additives in the gas that address this.

I’d get a water separator if I thought it would address any problem I’ve ever had or heard of but it seems to me that it has nothing to do with either the OP's problem of the problem I had in the previous post.

Am I missing something?

I agree that I don't think he had water in the gas. I think he flooded the carb probably because the needle was having a problem or he just overpowered it pumping. That led to gas dripping out onto the water and the hard starting.

Some of the problem could of been trash and if you are going to filter for that why not also think about the possibility of water in the gas which has increase with the use of ethanol in some gas.

We have a ....

http://purplesagetradingpost.com/sum...uel%20Tank.jpg

Macgregor 26S Outside Mods page 35

....19 gallon tank and I wanted to make sure that we also tried to cover the water in the gas possibility since we were going to Florida and didn't know what the gas situation was going to be down there.

http://purplesagetradingpost.com/sum...utside-35.html

We did find non-ethanol gas when we did fill up and drained the tank upon arriving home,

Sum

----------------------------------------

Our 37 Endeavour --- Our 26 MacGregor --- Trips With Both

http://purplesagetradingpost.com/sum...avour-sm-1.jpg

pvanv1 10-07-2012 07:57 AM

Re: Nissan 9.8 priming problem
 
In my experience, you had a sticky float needle. Yes, the Unikas filters work very well; we sell ots of them, and I have one on my Nissan 9.8A3. If the float/needle starts to do that habitually, it's time to pull the carb and clean it well, and possibly install a new needle.

timangiel 10-07-2012 12:03 PM

Re: Nissan 9.8 priming problem
 
Thanks everyone

RichH 10-07-2012 12:34 PM

Re: Nissan 9.8 priming problem
 
Quote:

Originally Posted by pvanv1 (Post 930414)
Yes, the Unikas filters work very well; we sell ots of them, and I have one on my Nissan 9.8A3. If the float/needle starts to do that habitually, it's time to pull the carb and clean it well, and possibly install a new needle.

Many particles in fuel 'form' or 'grow in size' (agglomerate -- small particles attracted together to become larger particles) downstream of filters.

Yes, filters are an important component of any fuel system but wont 100% prevent 'particle problems'. The typical 'filter' used in fuel usually is only approx. 85-90% efficient in removing particles at that ĶM 'rating' ... so its technically possible to 'pass a basketball' and still have the filter correctly rated at ~15ĶM, etc.


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