1986 dt140

[Bassmasterzero]

My Dt140 will run about a mile then stall...will crank but barely idle...I think the primer is the culprit but not sure...replaced fuel line, cleaned and rebuilt carbs....prime bulb wont pull fuel after it stalls...

[Solarman]

Check fuel pump, and the two clear discs (check valves) inside. If clear discs are fragmenting, there may be some pieces blocking the fuel flow at needle valve seats on the backsides? Not to mention poor pumping of fuel.

Good luck. Post back if find anything.

[Bassmasterzero]

forgot that I rebuilt the fuel pump....ordered the kit from Brown's point marine.....gonna get a new bulb today.....

[Solarman]

The check valves do not come with Suzuki kits. Only with the mikuni kits. Did you look closely at them when apart?

Post back when able.

[Bassmasterzero]

I pushed on them to see what the texture felt like....honestly figured they were alright because they Didn't feel brittle.....more like a firm silicone

[Solarman]

I'm not sure I understand this primer assy you're talking about. The fuel pump supplies fuel to each carb float bowl assy, until the needle valve shuts it off. If your motor runs a few minutes then stalls out, it sounds like either the fuel pump is pulling air causing carbs to run out of fuel, or the fuel pump is not pumping fuel properly/ adequately, and carbs are low on fuel again?

That's why I mentioned checking the clear discs (check valves) in the fuel pump, they have been found to be cracking/ breaking, and they don't come with Suzuki kits, only the mikuni kits.

I don't know about a primer system on your motor, and it doesn't show up in the parts pages I've seen?

Post back if you find anything. Good luck.

[Bassmasterzero]

Ok.....went through fuel system again....replaced primer bulb...now idles how it should.....saw nothing wrong with the valves in fuel pump....I did see a little fuel leaking from the bottom intake.....bottom carb may have the float stuck......looks like the shop ....I went through and found and replaced bad hoses...bulb was actually bad....New one holds fuel...but engine runs fuel out of line down to the primer bulb. A few pumps keeps it going...but wide open is still roughly a mile before t quits....ummm electric fuel pump?

[Bassmasterzero]

Ok.....went through fuel system again....replaced primer bulb...now idles how it should.....saw nothing wrong with the valves in fuel pump....I did see a little fuel leaking from the bottom intake.....bottom carb may have the float stuck......looks like the shop ....I went through and found and replaced bad hoses...bulb was actually bad....New one holds fuel...but engine runs fuel out of line down to the primer bulb. A few pumps keeps it going...but wide open is still roughly a mile before t quits....ummm electric fuel pump?

[Solarman]

Don't think you have an electric fuel pump? It's got carbs, not fuel injection. If it's sucking fuel out of the hose to the primer bulb, then you must have air getting into hose between bulb and tank. Otherwise, fuel would be pulled from tank, unless restricted, then the bulb would collapse (if not an extremely heavy duty bulb).

If any fuel is leaking from any carb, that needs to be corrected, or that cylinder will not run properly. If leaking from fuel lines, replace. If from throat of carb, float setting is slightly off, readjust.

While you have carbs off for fuel leak? Test the tps (throttle position sensor) by manual. It sends a signal to computer for throttle position, so computer can advance timing according to throttle position.

Good luck. post us back to let us know how it's going.

[Bassmasterzero]

Decided to try once more before removing the carbs...she ran great with the engine tilted high....then the primer bulb collapsed. I'm lost now.

[Solarman]

If bulb collapses, it is a sign motor is pulling fuel, but something before the bulb is restricting it. Check hoses to fuel/water separator, clean water separator replace filter. Then check hoses to tank fitting. Any old hoses should be replaced. Also check fitting at tank, if it has an anti-siphon fitting, it should be removed, or replaced.

Stop running around with the motor all tilted up. Fix the problem. If you aren't good with cleaning of carbs, find someone that is.

Do not mix up carbs, and do not mix up pieces for each carb (some jets in multiple carbs may be slightly different sizes-factory done to balance multiple carbs-fine tune.). Record the number of turns on each low speed idle jet, for each carb (count turns-screw closed till lightly seated-record for each carb). When re-installing all should be put back in same, lightly seat and back out #turns. Same on each carb.

Do not mess with any plates & linkages, or screws on outside (those can soak). All you need to remove; float bowl, float needle valve, needle valve seat, high speed jets, low speed jets, and any intermediate speed jets (on some carbs?). One carb may have a tps (throttle position sensor), leave on carb but keep tps above solution (do not soak - suspend with string, suspend basket, block carb up so tps stays above fluid/ solution level (wont hurt if splashed, but don't soak - removal may change position, some tps' require special meters/ procedures to adjust).

After soaking couple hours - more time for heavier cleaning, if needed, blow all pieces with compressed air to dry. Blow all jets, orifices, pas-sages, till dry.
re-assemble each carb with its pieces back together, but all float levels must be checked and set properly by service manual measurements. Check float adjustment by blowing air into fuel supply for each carb (small piece fuel hose), hold carb level, while blow into hose air should shut off when float gets level. If air doesn't stop when float is level, fuel won't stop either (fuel will run out of throat of carb if it starts/ runs). So either needle valve is bad, or float is not adjusted right, go back and reset float measurement. If float level is too low when you check with air, your motor will probably run out of fuel at wot/ full throttle. Carbs would have to be removed, and floats rest again. Very important to get right the first time.

Good luck, post back when able.

[BillCon]

If, the primer bulb collapsed then you have a restriction before the bulb leading to the tank, loosen up the fuel cap then hook up an air compressor to the line just before it goes to the primer bulb and blow it backwards to the tank listen for the bubbling sound, something may be lodged in the line or its got a kink in it, also check to see if the tank vent is working so a vacume doesnt form causing the primer bulb to go flat.