L. engine needs gradual throttle or loses rpm's. 98 sporster 1800

[Jim P.]

Twin 85hp engines L. engine loses rpm's if throttle pushed at same rate as right engine. Usually not a problem under a light boat load but much worse tubeing with 5 people in boat. If this is a carb issue can you try a carb cleaner in gas?

 

[RFoster130]

I would start with new plugs. You would be amazed at what a new set of plugs can cure. Then if that doesnt fix it, id start loking at typical fuel issues. That includes making sure you dont have the dreaded grey temp fuel lines, new filters and then rebuild the carbs. Since it seems to be isolated to 1 engine, i would suspect plugs or carb issue. Fuel cleaner is a waste. I try to start with simple & cheap and go from there.

 

[Jim P.]

I have not changed them since this issue so that is encouraging. I have noticed that plugs seem to be moist with ? oil/gas when I have changed them. I have changed them and then checked them after a couple of days in water and are moist with residue. Boat always starts fine but sometimes a harder start if we are anchored for a while. Boat has been great overall. What is involved in replacing gas filters if you don't mind.Thanks for your help!

 

[jhjesse]

I have not changed them since this issue so that is encouraging. I have noticed that plugs seem to be moist with ? oil/gas when I have changed them. I have changed them and then checked them after a couple of days in water and are moist with residue. Boat always starts fine but sometimes a harder start if we are anchored for a while. Boat has been great overall. What is involved in replacing gas filters if you don't mind.Thanks for your help!

Possible fuel delivery problem. I would pull the carbs and check the internal fuel filter. Its probably clogged.
Hard to start after sitting for a while sounds like leaky needles and seats. I would replace them while you have the carbs off cleaning them.
Unscrew the external filter/water seperator and clean.
If you have external fuel pump check to make sure it is pumping.

 

[Jim P.]

Thanks for your input. Will investigate with someone who knows what end is up. Have a good one.

 

[jhjesse]

Forgot to tell you to check the accelerator pump and make sure it is squirting gas into the carbs when pushing the throttle forward.

 

[Guest_User]

Forgot to tell you to check the accelerator pump and make sure it is squirting gas into the carbs when pushing the throttle forward.

ah very true, especially since that little gizmo is in the hose that you found could be blocked...lol...

 

[jhjesse]

ah very true, especially since that little gizmo is in the hose that you found could be blocked...lol...

LOL...Yeah I was going after leaking needles and seats when all that developed.

 

[mattbraafhart]

I had exactly same problem at the end of last season with my sportster, new plugs fixed it and these plugs were only a season old.