Low fuel pressure

[Havasulife]

Hi everyone,
I have two 1991 Sea Doo XP’s.
I am the only owner. They have been sitting off and on for the past 20 years. I ran them last two years ago and ran fine.
I recently decided they needed the tanks flushed and all fuel and oil lines changed. New pit cocks, Also had the carbs rebuilt with Mikuni carburetor kits. Pop off set at 26lbs.
Now they will only start and run with the choke partially on. (Lean)
To eliminate any errors I ran the fuel line and return line directly into an external gas can and I still have the same result. I can squirt fuel into the carbs and they seem to be ok. And coincidentally they both are doing this.
Any idea what this could be?
What can I try next?

 

[burtshaver2021]

Hi everyone,
I have two 1991 Sea Doo XP’s.
I am the only owner. They have been sitting off and on for the past 20 years. I ran them last two years ago and ran fine.
I recently decided they needed the tanks flushed and all fuel and oil lines changed. New pit cocks, Also had the carbs rebuilt with Mikuni carburetor kits. Pop off set at 26lbs.
Now they will only start and run with the choke partially on. (Lean)
To eliminate any errors I ran the fuel line and return line directly into an external gas can and I still have the same result. I can squirt fuel into the carbs and they seem to be ok. And coincidentally they both are doing this.
Any idea what this could be?
What can I try next?

When you were rebuilding the carbs did you have good flow with the carb cleaner from the pilot jet to the little holes that come out into the carb body? Mikidymac has a great thread on here that covers everything pertaining to rebuilding the carbs. You should have a read to see if maybe you missed something.

 

[Havasulife]

Yes I did. I went as far as pulling the carbs off of one of them again and had a shop rebuild them again. No change.
I will read Mikidymac anyways. Thank you.

 

[Havasulife]

When you were rebuilding the carbs did you have good flow with the carb cleaner from the pilot jet to the little holes that come out into the carb body? Mikidymac has a great thread on here that covers everything pertaining to rebuilding the carbs. You should have a read to see if maybe you missed something.

When you were rebuilding the carbs did you have good flow with the carb cleaner from the pilot jet to the little holes that come out into the carb body? Mikidymac has a great thread on here that covers everything pertaining to rebuilding the carbs. You should have a read to see if maybe you missed something.

Yes I did. I went as far as pulling the carbs off of one of them again and had a shop rebuild them again. No change.
I will read Mikidymac anyways. Thank you.

 

[burtshaver2021]

Yes I did. I went as far as pulling the carbs off of one of them again and had a shop rebuild them again. No change.
I will read Mikidymac anyways. Thank you.

Yes, hav a read, if you follow his carb rebuild thread then you can rule out the carbs.

 

[Havasulife]

Wondering…
If I rule out the carburetors.
Any idea of what else it could be?

 

[burtshaver2021]

I would bet it’s the carbs but if not I would check compression first as it runs the fuel pump, then look for possible air leak at crank seals, carb base gasket, fuel system

 

[Havasulife]

I would bet it’s the carbs but if not I would check compression first as it runs the fuel pump, then look for possible air leak at crank seals, carb base gasket, fuel system

I hope it is the carburetors but I was thinking. Would measuring the pressure coming from the block to the carburetor pump tell me if it is something else?
If so do you know what the pressure would need to be?

 

[burtshaver2021]

I hope it is the carburetors but I was thinking. Would measuring the pressure coming from the block to the carburetor pump tell me if it is something else?
If so do you know what the pressure would need to be?

If your talking about the pulse line from the crankcase to the carb, you don’t need to measure that pressure, if compression is good then there will be enough pressure there, is the pulse line a good black fuel line? Make sure it’s not a soft clear line, the softness can absorb some of the pulse

 

[Havasulife]

If your talking about the pulse line from the crankcase to the carb, you don’t need to measure that pressure, if compression is good then there will be enough pressure there, is the pulse line a good black fuel line? Make sure it’s not a soft clear line, the softness can absorb some of the pulse

Yes I was. They do have new black hose on them.
I have a compression gauge. Is there any trick when measuring compression on these?

 

[burtshaver2021]

Yes I was. They do have new black hose on them.
I have a compression gauge. Is there any trick when measuring compression on these?

No, no trick. Take both plugs out, ground the caps on the plug wires to the grounding posts, make sure you have a good battery, I’ve never found a difference with the throttle pulled or not, crank till maximum pressure is reached.

 

[Havasulife]

No, no trick. Take both plugs out, ground the caps on the plug wires to the grounding posts, make sure you have a good battery, I’ve never found a difference with the throttle pulled or not, crank till maximum pressure is reached.

Ok but I’m a little confused on grounding the caps?

 

[burtshaver2021]

Ok but I’m a little confused on grounding the caps?

You have some posts that look similar to this? Snap the caps into them

 

[Havasulife]

You have some posts that look similar to this? Snap the caps into themView attachment 66783

I don’t see those on mine? My Sea Doos are 1991’s. Maybe on newer ones?

 

[burtshaver2021]

I don’t see those on mine? My Sea Doos are 1991’s. Maybe on newer ones?

Not sure, I have a couple of 92xp’s but they are non runners so I haven’t looked at them in awhile. I can have a look, yours could have been removed

 

[burtshaver2021]

I don’t see those on mine? My Sea Doos are 1991’s. Maybe on newer ones?

On snowmobiles tha tv haven’t had the grounding posts I’ve just taken some wire and bent the one end to fit in the cap and grounded the other end

 

[burtshaver2021]

Not sure about your 91 but in the 92 the grounding posts are mounted to the top of the magneto housing