I have a 1999 Sportster with a Holley 4150 600CFS. Every year after the winter on the first start it cannot hold idle. When accelerated it will stay on and the RPMs will go up and down on a very rhythmic cycle. Lots of black smoke. No matter how many times it goes off and turn back on it will keep doing the same. If I let sit off for a few hours and turn it on the engine will start easily and run normal with no issues. The rest of the season it will be ok. It has been doing this for a few years.

Has someone experienced this? Any idea what is causing this?

6 minutes ago, solorex said:

https://www.marinehardware.com/

Here is the how to:  

Rudder's haven't really changed at all over the years, the above will be applicable to your boat.

 

 

The only difference will be instead of the wax rope packing, your rudder will have rubber o-rings that need replaced.  There is also a plastic bushing on the top of the rudder housing that can be replaced if you have excessive side to side play.

2 hours ago, Nitrousbird said:

An electric boat with a range extender gas engine is perfect.  For me, I'd basically never use the gas engine, as I'd run all electric typically and charge at home, but then would use the gas if on vacation or a long day on the water.  Range extenders for charging allow the motor to be smaller and more efficient, as you only need the engine to run at its most efficient RPM to charge.  You don't care about throttle response, power characteristics, RPM range, etc.  It is just a generator.  I'm a huge fan of this tech in both boat and vehicle applications where high torque is necessary.  

Plus the electric motor could be made to be sub floor and put a smaller more package efficient motor. 
Mazda is even looking at bringing back the rotary for hybrids.  Have a 200hp single rotor tucked up somewhere with a FAE.   

https://www.marinehardware.com/

Here is the how to:  

Rudder's haven't really changed at all over the years, the above will be applicable to your boat.

It's kind of hard to price, they are high new but the buying pool is pretty low. Especially if you don't want to ship them. 
I was able to score a single side off ebay for 250 last year, but there are pairs currently listed for 4k on ebay.
I'd say list them 1k - 1500 a side and go from there.