Low speed adjustment screw missing

[slowboatn]

Will this cause my 98 gtx limited to run lean? If it is completely missing? I did alot of work to it and now I think it is running lean. I got the FSM out and was gonna adjust the needle valve and one was missing on the carb on the front. I don't know which is mag or pto. Will need a new carb? I think it was broken off at one time and it didn't ever come out.

 

[slowboatn]

To the top!

 

[derek]

is it broken off in the carb, or missing? if broken off in carb it will run, but you can't adjust. if missing, it will barely run. extra air getting in-too lean, but you can fix it by installing another mixture screw.

 

[slowboatn]

It was broken off. It was removed and a new needle valve installed. Also found out that on the front carb, one of the brass nipples that a fuel line goes on had a huge crack in it. Had to replace the side of the carb. It cost me $64. I have spent like $300 on it. I ran it last night. It kinda bogs when first taking off. Then it goes away. I can only reach like 55 mph on a flat water. So I think the carbs need more adjusting. It runs and it isn't lean. I really like having it back.

 

[kustomkarl]

The carbs are set up this way; The front or "Mag" carb. is torward the end of the engine where the Magnito is located. The "PTO" carb is toward teh end of the engine where the "Power Take Off" or the Jet pump shaft is located. The carb adjustments are as follows;

The High Speed screw is set to "0". These have a plastic cap on them to keep them from being turned any more than 1/4 turn. The Low Speed screw is set to 1 1/2 turns. The screw has a pin through it. If you need to adjust the idle speed do NOT use the low speed screws to adjust it. Use the IDLE Screw to adjust both carbs at the same time. When adjusting the carbs be sure both carbs are in sync.

I hope this info helps you out.

Karl

 

[slowboatn]

Yes that is what the manual says. I'm just curious if this is something "I" can do or do I need to take it somewhere. It bogs off the line. Once on the water, runs fine. Has kind of a miss at 1000 to 2000 RPMs. I'm going to set idle today. It is too low. Idles around 1000. It needs to be 1500 in water. It is in the water.

 

[slowboatn]

Sorry. I see what you wrote now. Ok I'll try it. Right now in fact. Later!
Ok. Which way and how is zero located on the high speed screw? Is there one on each carb? Or only on one carb?

 

[slowboatn]

I adjusted the slow speed and idle. Now it is hard to start. Takes it a little while. It will start. Also, when I took it out of the water and was flushing it out, after I turned off the gas to it the idle went up to like 4000 rpm. Is this ok? Out of the water with fuel, it was idleing at 3000 before I cut off the fuel.

 

[kustomkarl]

I would still adjust the low speed screw so it starts better. The reason the engine revved up with the fuel off, is because the fuel mixture is getting leaned out due to lack of fuel in the engine...it was starving for fuel and was getting more air than fuel so it leaned out. This isn't a good thing as it could cause an over heat condition...if done all the time could end up causing premature engine seizure too.


Karl

 

[slowboatn]

Do I need to go in or out with them? I found the plastic cap for the high speed laying in the front storage compartment. Is the oil mixture an issue?

 

[kustomkarl]

The starting point is 1 1/2 turns out for the Low Speed adjustment. You could try in about 1/4 turn and if it doesn't help go out 1/4 turn from the original setting. Just be sure the marks align on the oil pump, and and the cables are in sync with the reaction of the throttle cable.

Karl

 

[slowboatn]

Ok that is ok on the oil pump and the cables. I've checked them out completely. I did notice that the throttle cable and another cable are crossed up. I uncrossed them. It was close to the Mag carb. I deduced that if turning the low speeds out, it will run richer; then turning them in will run leaner. Correct! So if it is bogging then I need to turn them in a little.