rev issues 98 sporster 1800

[Carlo]

I have a 98 sportster 1800 with twin rotax engines. I have 2 different problems but they might be related. My starboard engine usualy runs about 2000 revs higher then my port engine and now the starboard engine is also surging pretty bad too. I have checked my spark plugs and wires, air filter and fuel filter, and my impellars whch visably look good and don't wobble when they rotate. The surging only accours above 2300-2500 rpm. Does any one have any ideas what might be causing theese issues?

 

[timmyboy76]

xcellerator pumps

take carbs off and go thru them. The difference in rpm's, could constitute for difference in clearance at wear rings.

 

[Carlo]

Cool, thanks for the reply, I was planning on replacing all of the fuel lines (the ones on there are the black ones already) and clamps this wekend and getting the carbs out and cleaning the hell out of them. whith the RPM difference being as large as it is I didn't think that the wear rings could make that big of a difference unless one was completely gone. But I will have to try to check that now too.

 

[timmyboy76]

if lines are black, then no need to replace them, just go thru the carbs.

Didnt see the 2000rpm, thought it was 200. Yeah, thats a big difference, think it'll be something with fuel. Do compression test also.

 

[Carlo]

I forgot to mention I did the compression test already it was around the 120 mark on both cylenders and both engines. I was leaning towards a fuel issue as well. I figured it was sucking air some were along the line that's why I was going to go with new lines and clamps. I will just start with a carb clean and see were that goes, hopefully it will solve both issues.

 

[timmyboy76]

along those lines, replace the o-ring or entire fuel filters. Bad o-ring will pull air from there. Go to Autozone, get a 3 dollar fuel filter.

 

[Carlo]

cool, thanks again for the help I will see what happens this weekend after I get that done and let you know what happens.

 

[Carlo]

the problem was the internal fuel filter in the carb, once I cleaned that and replaced a few broken clamps on the fuel lines the boat ran great. thanks for all the help