Long starting time for 2003 Merc 150 XR6

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DMcCabe

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Joined
Dec 2, 2022
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Location
NW Illinois
I have a 2003 Nitro 288 Sport with a Merc 150 XR6. My issue is it takes a very long time to start the engine after it has sat for more than a few days. I pump the bulb and prime the engine prior to starting, always. The cranking battery is new. The spark plugs are new. I'm always able to get it started but it just seems to take a very long time. It "feels" like when the engine eventually fires and only runs for as long as the "primed" gas is in the system then quits. Then I prime again and it fires, and dies. Eventually it will fire and continue running. My assumption is that it takes that long for the engine to build the proper vacuum to pull the gas from the tank and run from that fuel source. But I'm no expert, just speculating. Any ideas? Thanks in advance.
 
I have an 03 xr6 as well and if I don't push the key in for 10 full seconds before starting, it is finicky. If i prime the bulb, level the engine and count 10 mississippi nice and slow while holding the key in, it usually starts the first time, also mine has to be completely level or a little trimmed down from level or it doesnt start. Hope this helps and it isn't some other issue!
 
I have an 03 xr6 as well and if I don't push the key in for 10 full seconds before starting, it is finicky. If i prime the bulb, level the engine and count 10 mississippi nice and slow while holding the key in, it usually starts the first time, also mine has to be completely level or a little trimmed down from level or it doesnt start. Hope this helps and it isn't some other issue!
I've noticed the same issue with the engine having to be perfectly level. Maybe I'm just not priming it long enough. I'll try your technique this weekend. Thanks.
 
Did it work? I have a 2000 xr6 and it runs great but takes a bit to start, I haven’t tried trimming it down too far because the area of the ramp is not very deep. Thanks
 
Yeah, I have to choke mine like I'm married to it or I don't think she'll ever get the dishes done, I mean start.
 
For all you XR6 guys me included ( I have one on my flats boat ) The "choke" is really what Mercury calls a (fuel enricher valve) It is a small electric fuel pump that has small fuel line that are attached to the bottom of the carb. fuel bowl (that's where it gets its fuel) then it squirts the fuel into the intake manifold. Then the vacuum as you crank pulls the fuel into the crank case and into the cylinder. So pumping the key switch 5or 6 times then holding when cranking should do it, If it cranks up then stalls pump it one or more times, the key is to crack the throttle warm up on the control box so it get enough air not to flood it. when running and wants to stall just pump the key.
 

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