My '03 400 4x4 is giving me fits. It has been cutting out here and there over the summer, but hasn't done it in a while. I chalked it up to bad gas or water in the system, when it started I would drain the bowl and it would run fine.

This weekend we went on a hunting trip. The first morning out , it wouldn't run unless the choke was on all the way. This was after warming it up. Coming back to camp it was the same thing, cutting out bad, no power, wouldn't run without the choke on. Getting back in camp I noticed gas pouring out of the overflow drain. I took the carb apart and adjusted the float to make sure the valve shut off. When I put it back together it worked just great, problem solved.

Coming back in the next morning, it was right back at it again. Sometimes it does it, sometimes not. Sometimes it happens when it's running, sometimes when it's just sitting if I don't turn off the gas. I don't know what could be causing it. Maybe some trash in the valve seat? I thought the insides felt like they weren't moving freely like they should. Maybe some Marvel oil wiuld help lube the system?

Help...

 

Carb needs a good cleaning. Remove the bowl, clean out the primary and secondary jets, clean the needle and seat good, blow out any trash thru the hole where the needle and seat are at (unhook the gas line before you do this) and you should be good to go.

 

Thanks. A good cleaning is what I was leaning toward.

 

yeah, overflowing gas is indicative of either a float issue or needle and seat issue. A good cleaning should take care of that. My 400 had a LOT of crap in the screen right before the needle and seat so if your's has the screen, be sure to clean that out god also.

Ernie

 

Cleanliness is next to Godliness they say. However an ounce of prevention is worth a pound of cure.

Point being keeping your fuel system clean all the time pays off in the long run.

I clean my air filter every 100 miles or so.

I also put Marvel Mystery Oil, dry gas, carb cleaner and alcohol in with my gas.

The Mystery oil will keep things lubricated to include the top end of the engine but also doesn't let things gum up and stick anywhere.

The dry gas helps out with moisture etc.

The carb cleaner keeps thing clean.

The alcohol ionizes the gas or should I say mixture (makes it a mist instead of big drops of gas), better distribution, air/fuel mixture and better ignition. Alcohol doesn't explode but burns on the surface - it will assist in making sure all the gas is burned. Alcohol also burns cooler thus your engine will run cooler and will burn all the gas and be more efficient. It also helps to burn the Mystery oil, carb cleaner and dry gas - thus you get some power from these additives. Anything that burns expands and when under compression will yield power.

A couple ounces of each per tankfull reaps the benefits.

Using the above plus "air-jetting" I can get 24 mpg from a 400 auto if I take is easy and just cruise at an average speed. I can get the mileage if I don't always jump on it or hot-dog, with the good mileage also means that it is developing good power. If it doesn't develop adequate power then you are not able to get good gas mileage because the engine has to work too hard.

But the main thing is that the fuel system is always clean and lubricated and thus lessens any gum from building up.

If you want to know more about "air-jetting" just simply do a search for "air jetting", I wrote a post about it and have some pictures as to what I did. Cost about $6.00 at the hardware store. It will allow you to use a big main jet and still get the correct air/fuel mixture. Bigger jet = more power and better gas mileage because it is more efficient with respect to HP to weight ratio.

 

Hey buckaroo50,

Do u use alcohol for racing or denatured alcohol?
and you said 2 oz's of each to six gal. reg gas..

 

<div class="FTQUOTE"><begin quote>Originally posted by: Mudbug5

Hey buckaroo50,



Do u use alcohol for racing or denatured alcohol?

and you said 2 oz's of each to six gal. reg gas..</end quote></div>

I use isopropyl alcohol (rubbing alcohol)- $1.99 for 16 oz. I check out an alcohol fuel additive at a store, the name was ??66 (can't remember the full name) and I checked the contents and it was the same so why pay $5.00 for 10 oz.

Racing alcohol would be better or a more suited alcohol for burning would be better. But probably any alcohol that you can dump on wood and burns probably would work. The idea is for the alcohol to ionize the gas and I suspect that most any alcohol would do. Heck, Captain Morgan may even work - lol....

But rubbing alcohol is 70% by volume, it is cheap and it works. You can pore some on your hand and light it and it will not burn your skin.

I put in about 2 oz per tank but you could put the whole bottle (16oz) and if it ran like crap then back off the mix. I basically just dump some in, it could be 2 oz or 3 or even 4 oz I just sort of guess.

But alcohol does burn and not explode and it does ionize gas and other flamable substances, and it also burns at a low temp, and it burns on the surface so anything in contact with it, such as gas will ignite. So you get complete combustion and full use of your gas and not just sending it out the tailpipe unburned. That is also attributed to the slow burning of alcohol. With the expense of gas these days we need to try and burn all the gas and get the benefit from it and not waste it, alcohol helps to do that.

 

The other 30% is water but as you can see the water is mixed and doesn't seperate from the alcohol so it will cause steam and that is good for cleaning and also power (steam engine). The reason that water will not run good in an engine is that it can't get hot enough or is not mixed in properly, dry gas helps to ionize the water so that it will break down the larger water drops to smaller ones and will evaporate under compression and heat (steam) in the engine the alcohol also helps to do the same thing.
By nature water is heavier and settles to the bottom and pure water won't work to well in a gas engine but if it is mixed in with the gas via (dry gas or alcohol) then it will produce steam and burn so to speak and in doing so steam is a good cleaning agent for removing carbon etc....
So the bottom line is that the 30% by volume in the rubbing alcohol may be helping and not hurting and the dry gas is just an added bonus for any moisture build up from condensation due to temp change and humidity etc or any water sucked in because of water holes etc...

 

Methanol would be better than IPA due to higher BTU's. Actually, a lot of dry gas (or gasoline fuel system de-icers) are 95+ percent methanol anyway! (Diesel fuel deicers don't use methanol) A lot of people give alcohols a bad name as far as fuel additives but the truth is that if you start with a clean system and run a decent concentration of alcohol, you'll never have a fuel related problem. BUT, if you have a dirty system and start running high concentrations of alcohol, odds are you'll get stopped dead in your tracks. I remember my one and only encounter with "gasohol" back in the 70's. I filled up my '71 Road Runner with gasohol and made it 3 miles before it cut off. I had to drop the tank and clean it out. I also had to remove all fuel lines and blow them out and pull the Carter AFB carb off and clean it out!!! Fuel stations had completely different regs then and their tanks were dirty so what we bought and put in our cars was dirty. Putting gasohol in dirty fuel systems "back in the day" was the temporary kiss of death for many cars. A lot of mechanics in my hometown were busy right after gasohol was introduced into the local market.

I have a "Flex-Fuel" truck but I will only buy flex-fuel from a local station that I saw install a brand new tank and pump system just for the flexfuel. I know that one is clean!!!

 

I guess the whole idea is to keep people on the trails and riding and a mix of Marvel Mystery Oil, dry gas and alcohol works for me so far. I have never had a problem that was related to carbs other than jetting and I fixed that with "air-jetting", cost me $6.00... (I think - CRS)... $3.00 to $6.00, in that range somewhere.