1998 Seadoo Sportster 1800 Surging

[Bobbuff]

Okay So for the second time now I am still having problems after about twenty minutes of good running time. Since I know Dr Honda will ask the compression on both cylinders is 140. The problems is that when cruising at 6500 for about twenty minutes my starboard engine begins to surge. Meaning it went from 6500 rpms to 4000 and back and forth repeatedly. This is the second time my boat has done this to me after a fresh carb rebuild.

So I rebuilt the carb the last time and took it out and it ran awesome for about twenty minutes and started acting up so I took it back in and rebuilt the carb replace the fuel lines and filters and since all the rain lately I went ahead and rebuilt the jet pumps and finally took it out yesterday. Ran awesome for about twenty minutes and it did the same thing. When it started acting up I pulled the choke to see if that solved the problem and nope it choked it out. Now it seems to have a little problem starting but eventually does. What could this possibly be??????

When this problem happens I almost instantly come off plane and have to limp back to the dock. Also only one motor is doing this the other runs awesome.

 

[docster]

Is it starboard motor doing it?

 

[Bobbuff]

Correct the other works awesome

 

[docster]

Yup I figured out why that's specific to the sportster 1800. The intake and exhaust vents to bilge suck. You may have a small exhaust leak but as it warms up in there from running you won't get much fresh air over to the starboard side. Run the blower while running and your surging will probably go away. If that works make sure you don't have an exhaust leak anywhere and just drive with the blower on.

 

[docster]

Try that and report back.

 

[Bobbuff]

Okay I will try but the time it started doing this I tried several small things and would take it back out only to find the same problem existed except it wouldn't even give me twenty minutes of good run time. Also I did notice a little water leaking from the exhaust area the last time I had it out.

 

[Dr Honda]

Yep... I agree.


it's either an exhaust leak, or your engine is getting hot. (I would test the temp sender, and make sure the buzzer works)