fouled a plug

[deiinc]

started up my 08 RS Vector GT the other day and fouled a plug doing it. How hard is it to change the plugs? Any reason to think it will be OK letting it set and hopefully dry out or fix it's self when I can get it out and ride it?
Got 5500 miles on it Is it time to change the plugs anyway?

Thanks for any help

 

[thrasher]

Unless you remove the plugs to look at them, you won't really know if you fouled a plug. Anytime you start your sled let it idle untill it's hot before shutting it down so the carbon can burn off the plugs. It's a four stroke so the plugs should last a very long time. Changing your plugs sure wouldn't hurt if that's what you think it is. At the start of the season, full tank of fresh gas with a can of SeaFoam to clean the fuel system, and a good run may cure your problem.

 

[swmichvector]

go with the iridium plugs if you change them. they are $10 a piece but worth every penny.

 

[Irv]

started up my 08 RS Vector GT the other day and fouled a plug doing it. How hard is it to change the plugs? Any reason to think it will be OK letting it set and hopefully dry out or fix it's self when I can get it out and ride it?
Got 5500 miles on it Is it time to change the plugs anyway?

Thanks for any help

Newb question.

Just curious if fouling a plug on a 4 stroke is as noticable as it is on a 2 stroke machine?

I have been firing up my sled every month since I purchased it(used) and I usually let it idle/rev it occassionally including spinning the track for at least tens minutes, do I have any worries fouling a plug doing this?

Also, when you change plugs, is it a good or bad idea to have the engine some what warm or should it be cold, as in not started for a least a couple hours?

 

[jamesc]

unless there are issues with the fuel / ignition system you really shouldn't foul plugs on a healthy four stroke. changing the plugs can be done at any time. you do need to be careful with aluminum cylinder heads and their threads. sometimes the aluminum can gall to the steel threads of the plug. assuming your sled is basically the same as my brothers 06 if it takes you more than fifteen minutes to change the plugs you're goofing off. if you're certain it fouled a plug i'd be looking for a cause, possible stuck carburetor float would be high on the list. if this were to be the case you need to be careful because it can possibly contaminate the oil with fuel and / or gas wash the rings which can cause engine damage.


as for starting an engine occasionally there are pros and cons to this. a fair bit of overall engine wear occurs during starting and warm up. combustion byproducts are corrosive and unless the engine is brought up to operating temperature where it can evaporate these they condense and collect in the engine, something you don't want. also you should never race a cold engine, let it warm up before flogging it.

 

[Groomerdriver]

unless there are issues with the fuel / ignition system you really shouldn't foul plugs on a healthy four stroke.

This is not true of you own a carb'd 4S as many of us with carb'd Vector's have found out. You CAN foul a plug(s) by not using the choke properly when starting the sled, or touching the throttle while the choke is on during a "cold engine" warm up situation.

Your statement might be true of FI'd motors...that I do not know.

 

[jamesc]

sorry i was making assumptions.

let me rephrase that, if you are familiar with non-EFI engine starting you shouldn't foul plugs. yes you can foul plugs if you use too much choke (or actually mixture enrichment) but the engine stumbling and huffing black smoke should be your first clue. the vast majority of these type carburetors don't use a traditional choke but a mixture enrichment circuit in them.

as soon as the engine fires you want to lean out (less "choke") the mixture to the point where the engine is running smoothly as possible. always use the minimum amount of enrichment you can to start the engine. if the engine stalls and you feel it's flooded turn the "choke" off, hold the throttle wide open (using CAUTION obviously) and crank the engine. if you've absolutely drowned the engine then you'll need to pull / clean / replace the plugs and possibly crank it to clear it again using caution because you have ignition sources depending on the engine.

on another note refiners change the vapor pressure of gasoline seasonally by varying the amount of butane blended into it. summer gasoline has a lower vapor pressure than winter which means it doesn't vaporize as easily and can possibly impact starting in cold weather.

 

[Irv]

sorry i was making assumptions.

let me rephrase that, if you are familiar with non-EFI engine starting you shouldn't foul plugs. yes you can foul plugs if you use too much choke (or actually mixture enrichment) but the engine stumbling and huffing black smoke should be your first clue. the vast majority of these type carburetors don't use a traditional choke but a mixture enrichment circuit in them.

as soon as the engine fires you want to lean out (less "choke") the mixture to the point where the engine is running smoothly as possible. always use the minimum amount of enrichment you can to start the engine. if the engine stalls and you feel it's flooded turn the "choke" off, hold the throttle wide open (using CAUTION obviously) and crank the engine. if you've absolutely drowned the engine then you'll need to pull / clean / replace the plugs and possibly crank it to clear it again using caution because you have ignition sources depending on the engine.

on another note refiners change the vapor pressure of gasoline seasonally by varying the amount of butane blended into it. summer gasoline has a lower vapor pressure than winter which means it doesn't vaporize as easily and can possibly impact starting in cold weather.

Great info Jamesc

 

[dhkr123]

if you use too much choke (or actually mixture enrichment.

The two things are actually one and the same.
You will note that the "mixture enrichment" circuit opens into a port on the INSIDE of the throttle plate. A more conventional choke closes a plate on the OUTSIDE of the MAIN JET.

In the case of a conventional choke, the vacuum created by the intake stroke draws fuel through the main jet since the vacuum is blocked by the choke plate. In these carbs, the vacuum draws fuel out of the enrichment circuit since the vacuum is blocked by the THROTTLE plate. So in this case, the THROTTLE plate acts as the CHOKE plate when the valve is opened.

In other words... they work exactly the same way. Call it what you will, but it is still a choke.

There are a few obvious reasons why they are implemented in this manner. The first is that there ends up being less junk messing with the airflow when the engine is running. It also simplifies things in that the control cables and linkage required for a conventional choke plate is more complex than just pulling on a spring-loaded valve. It also reduces the required length of the carb body.

 

[jamesc]

Call it what you will, but it is still a choke

no it is not, call it what it is...a fuel enrichment circuit.

if people want to refer to it as a choke that is fine i'm sure i do most if not all the time and it is NOT a choke. i pointed this out so those that aren't familiar with carburetion wouldn't visualize a plate closing in the carburetor bore when they operate the "choke" lever. many people might be familiar with a choke plate from years past but not familiar with a cold start enrichment circuit which is a superior method of cold start.

while it accomplishes the same result it does not work exactly the same way and "choke" the engine in the conventional manner a choke plate does.

it is a completely separate fuel circuit with it's own jet and different mode of operation. if a "choked" engine begins to flood opening the throttle with the choke on will not help and depending on type of carb can make it worse.

with an "enrichment circuit" if the engine begins to flood and you open the throttle the fuel enrichment circuit stalls reducing the fuel going into the engine. this happens because the pressure differential across the circuit drops when you open the throttle so it is more effective in clearing the engine.