U4EAHVAPORS
Active Member
I am going to try to get all info 1st time. This is a 2001 bombardier xp 947 (5531). I am reposting my ask a mechanic question.
2001 bombardier xp (5531) fuel delivery issue. Rebuilt carbs (mikuni kit & original spring reused) all fuel lines replaced, new coils with good spark verified, reserve tank selector switch throughly cleaned.
System will not circulate fuel when fuel system installed correctly, pressure seems to build but jugs end up dry.
IF an external very small ~10psi fuel pump is installed to the carb fuel intake, (8.4mm line) the engine pretty much fires right up and is great all day at high end (rpm) BUT will only idle at a "sweet spot" of half choke. When doing this technique the fuel return is actively returning fuel to tank through return port (see through line). All cooling water circulates properly. (This is out of the water) and the water temp is never over ~170 degrees, jugs are touchable not very hot. The tank was 100 % emptied and rinsed and emptied again under pressure through the "vent" line (pushing air through line towards tank) and out the fuel filter "in port" line using approximately 50 - 80 psi compressed air.
So the system holds pressure. When the two vents that proceed from the vent out port of the tank are left open they will both spew gas and air. And are absolutely routed correctly ( checked & triple checked). These valves (air-in only [under seat/handle bar] valve & pressure release [ just above water line next to where exhaust water shoots out] valve work properly) are presently installed correctly and that made the engine run a "tad" better, not significant.
The rave valves have been cleaned and an adjustment of closed (screwed down tight) of 2 turns out and 1 turn out respectively, with minimal effect.
After rebuild the high jet is full to the right and low was as close to previous - which was approximately 1.4 turns out from full tight. The idle screw has not been touched by me.
I hope this is enough diagnostics.
Was planning on adjusting low jet and possible idle jet.
One last thing - the very small oval part in the carb kit (please see picture) was NOT used. However I did not see these installed when I disassembled the carbs, and have not since found either one lying around ( if it fell unnoticed). That does not mean it is not the problem, as the same starting technique worked (small pump) before carbs were rebuilt. The engine definitely ran better after rebuild- previously it would not idle AT ALL and ran rough in general throughout rpms range
To update I checked my diagram, it shows this carb part in place. It is not numbered but it is with small plate and screw and they are between the #40 bracket
Next update: I did find the "reed?" Valve in my soaking solution. Only one recovered, so the next question is do i order the thinner to spec vavle or go with the mikuni replacements, slighly thicker. Or use 1 original I have and 1 replacement. Please **Help**
Next update: placed reed valve (in picture) on both carbs. Engine will now fire right up and idle on it's own, with a tendency to increase in rpms over time, 30-45 seconds. This can only be done with above mentioned fuel pump procedure. When I connect factory fuel system setup after running engine with this procedure (ussing the small pump) the engine will run for a minute or so and die, with plenty of gas in the tank.
The baffle in the tank with the 4 ports is mounted crooked, leaning left ( if sitting in the seat). Would this have an effect?
2001 bombardier xp (5531) fuel delivery issue. Rebuilt carbs (mikuni kit & original spring reused) all fuel lines replaced, new coils with good spark verified, reserve tank selector switch throughly cleaned.
System will not circulate fuel when fuel system installed correctly, pressure seems to build but jugs end up dry.
IF an external very small ~10psi fuel pump is installed to the carb fuel intake, (8.4mm line) the engine pretty much fires right up and is great all day at high end (rpm) BUT will only idle at a "sweet spot" of half choke. When doing this technique the fuel return is actively returning fuel to tank through return port (see through line). All cooling water circulates properly. (This is out of the water) and the water temp is never over ~170 degrees, jugs are touchable not very hot. The tank was 100 % emptied and rinsed and emptied again under pressure through the "vent" line (pushing air through line towards tank) and out the fuel filter "in port" line using approximately 50 - 80 psi compressed air.
So the system holds pressure. When the two vents that proceed from the vent out port of the tank are left open they will both spew gas and air. And are absolutely routed correctly ( checked & triple checked). These valves (air-in only [under seat/handle bar] valve & pressure release [ just above water line next to where exhaust water shoots out] valve work properly) are presently installed correctly and that made the engine run a "tad" better, not significant.
The rave valves have been cleaned and an adjustment of closed (screwed down tight) of 2 turns out and 1 turn out respectively, with minimal effect.
After rebuild the high jet is full to the right and low was as close to previous - which was approximately 1.4 turns out from full tight. The idle screw has not been touched by me.
I hope this is enough diagnostics.
Was planning on adjusting low jet and possible idle jet.
One last thing - the very small oval part in the carb kit (please see picture) was NOT used. However I did not see these installed when I disassembled the carbs, and have not since found either one lying around ( if it fell unnoticed). That does not mean it is not the problem, as the same starting technique worked (small pump) before carbs were rebuilt. The engine definitely ran better after rebuild- previously it would not idle AT ALL and ran rough in general throughout rpms range
To update I checked my diagram, it shows this carb part in place. It is not numbered but it is with small plate and screw and they are between the #40 bracket
Next update: I did find the "reed?" Valve in my soaking solution. Only one recovered, so the next question is do i order the thinner to spec vavle or go with the mikuni replacements, slighly thicker. Or use 1 original I have and 1 replacement. Please **Help**
Next update: placed reed valve (in picture) on both carbs. Engine will now fire right up and idle on it's own, with a tendency to increase in rpms over time, 30-45 seconds. This can only be done with above mentioned fuel pump procedure. When I connect factory fuel system setup after running engine with this procedure (ussing the small pump) the engine will run for a minute or so and die, with plenty of gas in the tank.
The baffle in the tank with the 4 ports is mounted crooked, leaning left ( if sitting in the seat). Would this have an effect?
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