Maintaining a Nissan/Tohatsu 6hp

ronellis · Post by **ronellis** » Oct 5th, '08, 22:50

Anyone else have problems with fuel going bad and clogging up the carburetor on a Nissan or Tohatsu 4-stroke 6 hp motor? The Nissan on my dad's CD25 will start and idle fine, but will quit in gear under load. I understand that the key is to run it a least once a month, but unfortunately, with the boat and motor kept 200 miles away, that's not always possible.

Is there any fuel additive that can help the carburetor clean? Is there any way to clean it yourself? The Nissan manual states that it should only be serviced by a dealer.

How long can Sta-bil actually keep gas fresh? I have always bought gas one gallon at a time and used Sta-bil, but it can take six months or more to use that gallon of gas. Is that contributing to the problem?

Thanks.

ronellis · Post by **ronellis** » Oct 6th, '08, 08:24

One thing I should have added is that we always disconnect the fuel tank and run the fuel out of the motor when we're done using it.

A few years ago, a Nissan dealer, who had just cleaned the carburetor, told me not to run the gas out. He said the jets in the carburetor were so small that it was better to leave more gas in there than less. I followed his advice but was clogged up again soon thereafter. After getting the carburetor cleaned by a different shop, I have always run the gas out, and have had fewer problems.

I think conventional wisdom with outboards is to run it out. Do any of you Nissan/Tohatsu owners do anything different?

Thanks again.

doubleb · Post by **doubleb** » Oct 6th, '08, 09:06

STA-BIL gas treatment. Get it at Wally world. auto parts type stores.
don't leave home with out it.

bottomscraper · Post by **bottomscraper** » Oct 6th, '08, 09:24

ronellis wrote:
How long can Sta-bil actually keep gas fresh? I have always bought gas one gallon at a time and used Sta-bil, but it can take six months or more to use that gallon of gas. Is that contributing to the problem?

Thanks.

From the web site FAQs:

How long will STA-BIL Fuel Stabilizer keep fuel fresh?

For 12 months when mixed into fresh gasoline. Doubling the dosage will keep fuel fresh for up to 2 years.

http://www.goldeagle.com/sta-bil/faqs_s ... a-bil&ID=2

I have been using STA-BIL in all my small engines (lawn mowers, chains saws, weed wacker, outboard...) for 30+ years. I kave never had a carb problem. I did have a problem with our Nissan 3.5 hp with a sticky reed valve, behavior was similar to what you are having but since your engine is a 4 cycle that can't be the problem!

ronellis · Post by **ronellis** » Oct 6th, '08, 21:03

Since we have always used sta-bil, and we don't exceed a year, I'm thinking that a bad fuel supply is not my problem.

Have any other CD25 owners with Nissan/Tohatsu 4-strokes had this problem? Have any of you cleaned your own carburetor? Any tips?

Thanks for your responses thus far.

Sea Hunt · Post by **Sea Hunt** » Oct 7th, '08, 00:02

Interesting and timely post. I have been thinking about putting something in my fuel but was not sure what, if anything to use. I had read about Stabil and was going to ask the board about it.

When I was young, I worked on cars with my Dad and I was always wanting to put fuel additives (like STP), etc. into the tank, and spraying the carb. with all kinds of stuff. My Dad was always reluctant to add anything. As I got older, I stopped putting anything in to the gas in my vehicles - whether cars or trucks. I think generally this stuff does not do much good, if any, especially if you are putting in new fuel every week or less

Now, with the gas having 10% Ethanol, it may be helpful to have an additive to keep things clean and fresh. Not sure.

With my small 6 HP Suzuki, I use so little gas and the gas sits in either the onboard tank (small) or the external tank for weeks that I have thought I should add something to try to "preserve" it a little.

I am going to give StaBil a try.

If I have used the external tank I always disconnect the tank at the end of the day and then run the O/B until it stalls out to get the fuel out of the lines. Someone on this board recommended this months ago and it makes a lot of sense. Of course, this cannot be done with the onboard tank and line but I think it is just a short gravity feed line anyways (although I have not yet taken the tank apart to examine it carefully so not sure).

doubleb · Post by **doubleb** » Oct 7th, '08, 05:58

Ronellis

I cleaned the carb on a previous Nissan 6 I owned. It was doing just what you describe. It Idles fine and stalls under load.

Remove the carb. disassemble over a secure surface. Take note of what goes where.
A digital camera comes in handy.

I found my main jet with a restriction. A little poking with a small piece of wire, And good PB Blaster bath. Reassembled, and it ran fine.
I might have just got lucky. But it worked. The motor was new to me so I can not verify if Sta-Bil was used in the fuel.
But I do use it in all my gas powered equipment. So far I have had no problems.

Check your fuel filter

Good luck

Brian

Wayne Grenier · Post by **Wayne Grenier** » Oct 7th, '08, 10:58

what you and thousands of other people are dealing with is that the ethanol we now put in gas causes the gas to turn into "crap" in a matter of weeks-(I hope you like my scientific explanation)-it doesn't seem to bother cars with fuel injection but any motor with a carb is suspect to this problem-simply put-this New gas doesn't age well-it goes bad in a matter of weeks-not months-I have had problems with my lawnmower-outboard-etc-all because of the gas-
I only use fresh gas-buying a little at a time but I have been told there are additives coming onto the market to deal specifaly with the ethanol-motorcycle shops are carrying them as the ATV guys are having the same problem-
Fortunately once you take apart one small carb-you can take them all apart-all are designed to be easily cleaned-
1st locate the gas hose from the tank to the carb-loosen the hose clamp and pull the hose off and drain the gas-what you do with it I have no idea-the carb will have a screw drain plug on the bottom of the bowl-loosen it and the gas will drain out-continue to loosen it and the bottom half of the bowl will fall into your hands=the float and the needle valve will now swing down but they shouldn't fall out-just make sure you are working in a clean area and have a cloth or something on the ground in case any little parts decide to fall out-
The bottom half of the bowl can be cleaned with carb cleaner and a rag-and spray carb cleaner up into the carb from the bottom of the bowl and clean everything-put it back together and use fresh gas-
also the 1st time you try to start the motor-take the plug out-spray starting fluid into the cylinder and put the plug back in-now try to start the motor-and it should start right up
allways suspect the gas 1st-especially these days-
its worth it to find a junk lawnmower or such and just take the carb apart for fun-there are many more detailed descriptions on the web about carbs-floats-needle valves etc-it is very simple once you do it a couple of times-and %99 of the time all you have to do is take it apart-clean it and put it back together again-
Open up you own repair shop and do the above 10x per day and charge $75 per engine-
(My brother is a motorcycle mechanic)
There are more detailed things that can go wrong such as needle valves that are worn down and don't shut off the flow of gas causing the engine to flood and floats that get pinhole leaks and don't float anymore (causing the engine to flood) but I don't think that is your problem-its this crappy gas the are selling today-

bottomscraper · Post by **bottomscraper** » Oct 7th, '08, 13:18

I just stumbled across this, a new Marine version of Sta-Bil

http://www.goldeagle.com/sta-bil/stabil_marine.htm

Serge Zimberoff · Post by **Serge Zimberoff** » Oct 8th, '08, 14:06

I have always run the carb bowl empty and have never had a problem. That said, I don't keep any fuel older than 6 months anymore (even with StaBil added). I pour what hasn't been used in the boat into the car as it was noted in an earlier post, cars don't seem quite as fussy and it gets used up right away (darn). It is a bit of a drag but saves a lot of problems.
Serge

pete faga · Post by **pete faga** » Oct 8th, '08, 22:02

I bought a brand new Tohatsu and the dealer said to NOT run it out. I guess i 'll know in the spring.

Joe CD MS 300 · Post by **Joe CD MS 300** » Oct 9th, '08, 06:08

From what a dealer told me, the argument against running it out is that the engine (if it's 2 stroke) will get insufficient lubrication as it runs out of gas. Not an issue with a 4 stroke.

seajunkie · Post by **seajunkie** » Oct 22nd, '08, 23:49

I have a 2005 Nissan 6HP. My motor would idle ok, but when I put it in gear it would always stall at the most inopportune moment.

I spoke with an outboard mechanic who led me to do the culprit. These motors were designed to be very easy on the environment. They run very very lean. They must be tuned perfectly to run correctly. This is hard to do on a sailboat when the motor is an auxiliary tool.

What I did was drilled out a brass cover that covered the carb fuel adjustment. Once that is removed you can use a standard screw driver and richen the mixture. With more fuel my motor has run great all season. It took me about twenty minutes. I had to disconnect the gas tank in a few places to get to the cap the covered the screw.

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Maintaining a Nissan/Tohatsu 6hp

Maintaining a Nissan/Tohatsu 6hp

Re: Maintaining a Nissan/Tohatsu 6hp

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