Read my Spark Plugs (PICS) Need help tuning Carbs

[Jeff_5_7]

I have posted on this before and am getting closer.

I am working on tuning the carbs on my 96 GTX.

Settings are Highs 0 Lows 1 1/4

With a brand new set of plugs it will run 30mins and then it foul the MAG plug and start sounding like it is backfiring and will start dropping rpms at full throtle and quit running good).

I am running premix 32:1 and aftermarket Flame Arestors . (Dont know what brand and i never rejetted or changer pop off )

Also while riding for the 30mins max rpm was about 6500 and max speed 45mph. My other gtx the exact same would run 7000rpm and 55 mph.

Here are pics remember this is after riding for 30 mins plugs were brand new.

Here is MAG (its black and oily)

Here is PTO (golden brown i think its right where it needs to be)

HOW CAN I FIX THIS?

Will putting the stock airbox back on fix it or is there something wrong with the MAG Carb?

 

[6KJR]

The stock airbox i doubt would change anything. 32:1 is pretty rich. Most people will run 40-50:1. I myself run 45:1.

How did you do your plug chop? Generally there is a procedure to it. Are you following those guidelines? Just wanna make sure because it's important.

If you are, and are you of adjustment screw turning, order a smaller jet for that carb. But if your fouling a plug maybe you should look Into checking for another issue. Such as float arm level, pop off pressure, clean carbs. Ect.

 

[Dr Honda]

32:1 is too much oil for a seadoo... and if you are running that much oil, your PTO plug looks light.

Change to 40:1, and open your PTO high mix screw 1/4 turn, Put in a fresh set of plugs, and check them again.

Because the pics are blurry... it's hard to actually see what the plugs look like. If you are using a regular camera, there is a close up mode. (normally looks like a little flower)

And finally, do a compression check for us. As the engine wears, and the compression falls off... the plugs will start to darken up, (even with a proper mix) and there's not much you can do about it, other than to run a hotter plug.

I know on a bunch of other boards... I see threads on reading piston wash, and plugs, and they are trying to run their ski's on the ragged edge for peak performance. But, my personal opinion is to run them on the rich side. A little extra fuel keeps the piston crown cool, and the engine safe. (obviously, you don't want to be fouling plugs every ride either)


OK... this is the last thing... what kind of plugs are they??

 

[Jeff_5_7]

I just took it out and rode it around close to the boat ramp until it started rummimg bad again which was 30mins. I didnt do an actual plug chop.

So you think switching to 40:1 will fix it?

Why is it only fouling the MAG Plug. I know thats the carb with the fuel feed.

 

[Dr Honda]

I just took it out and rode it around close to the boat ramp until it started rummimg bad again which was 30mins. I didnt do an actual plug chop. .

People may dissagree... but unless you are tuning a race engine... you don't need to do a "Plug Chop." BUT... you have to be aware of the throttle setting you are running at. If you think you want to change your main jets, but were only running around at 1/2 throttle... then it's not a valid test.

So you think switching to 40:1 will fix it?.

It will help. What kind of oil are you burning?

Why is it only fouling the MAG Plug. I know thats the carb with the fuel feed.

Could be low compression, crank is out of index, or the crank seal is leaking, and drawing in extra oil on that jug. Also... the pop-off pressure in the MAG carb could be low.


I added to the post above... you may want to reread it.

 

[Jeff_5_7]

NKG BR8ES Brand New at my Local Napa. I did a compression test on this motor about 3 weeks ago 150 psi both cylinders. I just replaced the top en about a month ago so it s pretty close to brand new.

 

[Jeff_5_7]

Its quicksliver (i believe} PWC oil got it form local walmart i ran it in my other GTX fine all last summer.