587 carb questions

[Camarojoe12]

Hey all I have an 89 yellow rotax single carb. I have some questions about adjusting the carb. The pulse line going to the pump has gas in it is this normal ? Also the ski will start up and rev nice but will not idle/stay running. It has all brand new oil and fuel lines rebuilt carb and pump, I also cleaned out the oil and fuel tanks. Any advice welcomed

 

[mikidymac]

No, with water or fuel in that line the pump won’t work correctly. Chances are there’s fuel in the pump too that shouldn’t be there.

 

[Camarojoe12]

No, with water or fuel in that line the pump won’t work correctly. Chances are there’s fuel in the pump too that shouldn’t be there.

Thanks for the reply. I’m going to take the pump apart my self and see what it looks like. The po said it was rebuilt along with the carb

 

[Camarojoe12]

No, with water or fuel in that line the pump won’t work correctly. Chances are there’s fuel in the pump too that shouldn’t be there.

So I took the pump apart to check things out. I found one of the gaskets upside down, and one of the rubber retainers for the check valve not fully seated. I will install and retest. As for the pulse line going to the pump from the crank case, I put my thumb over the end of it and it has a great pulse when I crank it over. When I release my thumb it sprays fuel out of it. Could that just be residual from the pump allowing it to flow back? Or should I be worried about something else?

 

[mikidymac]

Sounds like the crankcase might be full of fuel.

Judging by what you found it sounds like whoever did the carb had no clue what they were doing.
I would suggest rebuilding the carb correctly per the Carb Rebuild sticky in this section with all new verified Genuine Mikuni parts or you will be chasing your tail the rest of the summer.

 

[Camarojoe12]

Sounds like the crankcase might be full of fuel.

Judging by what you found it sounds like whoever did the carb had no clue what they were doing.
I would suggest rebuilding the carb correctly per the Carb Rebuild sticky in this section with all new verified Genuine Mikuni parts or you will be chasing your tail the rest of the summer.

Thanks for the info. I was thinking of replacing it entirely as I saw in a few places to stay away from the single round Mikuni which is what it has

 

[etemplet]

Pull the rotary valve cover and have a look. You can see the crankcase internals, rotary valve condition, and clean up whatever is in there. Good Luck !

 

[Camarojoe12]

Sounds like the crankcase might be full of fuel.

Judging by what you found it sounds like whoever did the carb had no clue what they were doing.
I would suggest rebuilding the carb correctly per the Carb Rebuild sticky in this section with all new verified Genuine Mikuni parts or you will be chasing your tail the rest of the summer.

I have the original take off dual carb set up, I’d like to use one of those carbs in place of the original. They look identical except the fuel nipple,and are stamped pto/mag and the jet is different. So the jet from the single set up has a hole marked 6.0 and the carb from the dual has no hole and is stamped 0.0. Questions I have are will the carb with no hole run as is?Or Do I need to drill it out to match?

 

[mikidymac]

I don't think the dual carbs are the same size as the single carbs although the both claim to be 38mm. I would check the throttle plates to see if they are both stamped the same size as well as measuring both ends of the venturi.

Those old round body carbs are a pain.

 

[Camarojoe12]

I don't think the dual carbs are the same size as the single carbs although the both claim to be 38mm. I would check the throttle plates to see if they are both stamped the same size as well as measuring both ends of the venturi.

Those old round body carbs are a pain.

Both look identical, throttle plates are both stamped 150 And as far as I can tell the the venturi is the same as well

 

[Camarojoe12]

I was informed that the part I was referring to is not a jet. So what exactly are they?

 

[mikidymac]

I honestly don't remember. Been over 25 years since I touched a round body carb.

 

[Camarojoe12]

I honestly don't remember. Been over 25 years since I touched a round body carb.

I’m wondering if I drill it to match the other carb if it’ll work. It’s the only notable difference