2004 Sportster Starts Runs Rough Stalls

[Matt Braley]

I said I'd never get a 4 stroke and probably shouldn't have. It was pretty and cheap and he fired it right up and ran it on the hose. Now that I'm home I realize that it fires right up everytime but starts to stumble then dies. If you give it a sec and put the key back on it idles smoother and you can give it a little throttle, otherwise it always stalls as soon as you try to give it throttle.

I gave it a set of new plugs. There is no water in oil, oil in coolant thank god. I siphoned out as much fuel as I could and put in a full tank of 93 with a can of Seafoam before I even tried to run it. I can hear the fuel pump kick on when I put the DESS key on. The guy said it ran but I know he let it sit for a year to a year and a half(and he may have knowingly passed me a biscuit). What should I do next?

 

[10forty2]

It sounds suspiciously like a fuel problem to me. Should be a fuel filter somewhere in the line. Might be some trash that won't let enough fuel through when revving it. I'd replace that, if you can find it. It may also take a few runs for the Seafoam to get rid of that old gasoline varnish that can build up when it sits in a tank and in the lines/injectors for a while. If you only put one 16oz can of Seafoam in a 40 gallon tank, that's probably not enough for results. Recommendation for normal use at every fillup is for 1 oz/gallon of gas, and it won't hurt to even run it a stronger than that, maybe 2oz/gal, for the first couple of tanks until it can completely dissolve and clean out the old buildup. Make sure you put in ethanol-free gas as well.

Go ahead and change the oil/filter(s) and filter housing gaskets too. Sitting like that and not having the engines up to operating temperature in over a year will allow condensation to build up and cause other engine problems. It won't necessarily cause the problem you're describing, but it will cause piston/cylinder problems.

 

[Matt Braley]

Thanks for the response. It has fresh oil and filter. Yes it does seem like it's running out of fuel. The fuel pump seems cheap and easy to change so I may try that.

 

[mikidymac]

You probably should have made a fake name to post your 4-Tec boat questions with Matt. Shame on you!

 

[Matt Braley]

Yeah I'm burned at the moment for breaking my rule and buying 4 stroke. Now I've got to get it straight because I've got money tied up in it and no good place to store it. I didn't seek it out, a guy actually offered it out of the blue next to a house my tree service was working at. I thought 2500 was a no-brainer but now I'm 3k in a broken boat.

 

[IDoSeaDoo]

I had an issue running out of fuel on turns. The cause was clogged in-tank filters. They go for about $20 and sit on the bottom of the in-tank fuel pump. It could also be your fuel pump. The fuel line has a test-port, but I've read threads on how hard it is to find a test adapter. The ones from Autozone sure don't have the right fitting. I think I removed the shrader-valve out of mine and clamped a hose onto it with a gauge on the end to get my fuel pressure reading. The fuel pumps can also be replaced with a lower cost automotive version. I hear they're identical to the OE.

 

[Matt Braley]

Hey thanks for chiming in Ido. Hope you and yours are doing well, I'm sure you are.

Yes after 14 years it would probably be a good idea to look at those filters and pump. I see them cheap on ebay. I'll try that next.

 

[Matt Braley]

It seems to have liked the new fuel pump kit. I ran it on the hose and can tell a positive difference (like it not clonking out lol). The real test will be in the water but fingers are crossed.

 

[Matt Braley]

Water test failed. I got the 12mm adaptor for my compression tester and luckily all three holes were between 165 and 170psi. I think I'm going to hire the dealer to tell me what is wrong with it instead of continuing to throw parts at it. I'm not getting a Candoo, I'll be going right back to my 2-stroke only stance.

 

[Matt Braley]

The dealer had to work with it for a long time changing parts and trying to clear codes. Finally one of the employees took an ECU from his personal boat at home and plugged it in. That in addition to one map sensor cleared all my codes. They charged me $200 for this, well worth it as long as they are right.

I called up my good friends at Westside Powersports and they had the parts and shipped them right out. Apparently the inventory on these early year 155hp "130" and the "133" ECU's are running thin. Jess had a 215 ecu from a RXP re-flashed to the lesser HP version and now it accepts any DESS key. Can't wait to try it.

 

[svtjoe98]

It does sound like an Ecu issue. Try to reseat the main connector on the ecu. Be careful to not bend the pins.