NICE CATCH Rustkolector!! You probably saved somebody some anguish. I was looking at the same engine and wondering about it but then I remembered my friends Yanmar pump runs the same way, from the cam gear. That must be one hell of a strong gear.

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  I am not an engineer by any means but I think with all due respect that your estimates of HP
 gain are high for intake work. I work for a vehicle manufacturer and yes I realize gas engines
 and diesels are different beasts, but I know for a fact that manufacturers of vehicles will spend
 hundreds of thousands of dollars and thousands of man hours on a flow bench or wind tunnel
 for a 1 HP gain. Granted those engines are further down the volumetric efficiency chain and
 harder to make a significant gain.Even though the Lister is a slow speed engine I think it still
 plays by the same rules . I think you would get much greater results if you just did a plain old
port match and valve bowl blend. From just listening to the caliper of post on the board I think
 that most if not all could do the job quite well. I have seen gains of 70+HP on NA 300 HP
 engines with a full port, bowl job. Go into the combustion chamber and work on it and your
talking another 20Hp gain.I think a 20% HP gain would not be out of the question. 

  Martinwill, I would go raw water cooled in fresh water bodies and wet exhaust, its more comfortable on the ears. If there are any dips or crowns in the exhaust piping as the water builds and flows it will give your engine its own unique sound.

  I'm not familiar with the petter block integrity but I think that most engines would last in fresh water quite a long time if raw water cooled. For example my fathers boat had two Hercules block (Chris Craft conversions) in it. They were 1948 200HP, 404ci 6 cylinders. He bought them new and they were run in the Chesapeake Bay/Delaware River area until 1988. In that time the only problem ever incurred was in 1981 on one engine, the exhaust manifold rotted through leaking water into the cylinders and causing a misfire. To put it in perspective The engines were so worn-out that for every 35 gallons of fuel burned they would burn a gallon of Fox 50w oil. But they started every time and ran without a problem so they stayed in the boat until it wore out.(1934 Wheeler custom sedan 40').My dad had an another boat a1950 Matthews 42' he put Chrysler 440s in it in 1970 and they ran until his death in 2004 and they also were raw water cooled. The only problems with them were that the exhaust manifolds would rot out or clog up about every 10 years.

What I'm saying is what ever the route you go don't worry about it just have fun. 

  Martinwill, there are a few different types of keel coolers. The first is a series of pipes that runs the length of the keel in series front to rear. Next is a series of pipes running the length of the keel that are connected to a main feed pipe and branch out in parallel like the tubes in a car radiator. They both carry an anticorrosive coolant to and from the block and heads and sometimes the oil and trans coolers. They both will require a circulator pump and a raw water feed pump. The raw water feed pump will still carry water to the manifolds and risers if equipped. The circulator pump will move the coolant to and from the block and heads. You will also need an expansion tank and overflow tank. The downfalls of the keel cooler are, it can be damaged by collisions with bars, reefs, the bottom, debris and corrosion. It also has another enemy, barnacle type growth that can diminish its cooling capacity. If the boat is run regularly, this is rarely a problem. The benefits far outweigh the pitfalls. The shape of the pipe is usually round and of an anticorrosive material. If you are working with a solid keel the feed and return pipes can be put through the garboard plank or area next to the keel. Keel coolers are normally used in slow moving boats (displacement hulls) not planing hulls because of the drag associated with the external piping.

There is one other type cooler but it really doesn't apply to you unless you are very ambitious or building a big Tug, its called a courting nozzle. This type is a circular shroud that goes around the prop with a hollow center to house the engine coolant. The nozzle in some cases turns in series with the rudders to vector the prop wash where it is needed most.
I hope this info helps.
Bluecometk.

Thank you all again for your answers and info.

 Doug, I did not check the rectifier because me testing it would be like a first grader doing calculus. Engines are my thing not complicated stuff like that. I was going to buy the Utter CD to help guide me through it.
 
 Well, I performed another test today and the findings are below.

 Control:
              Temp:          92F
          Humidity:           88%
           Altitude:           12'
               Fuel:            (yellow) fuel oil

W. O. T.  on the linkage:
 
 No load  123V ,    62.5 Hertz    both legs
 1500W   115V,    60.4 Hertz     both legs  total  3000W
 3000W   106.6,    56.6 Hertz     both legs  total  6000W   no smoke    notable load no RPM loss
 4500W   106.4,    55.5 Hertz     one leg     total  7500W   some smoke  notable load  no rpm loss
 3250W   106.5,    55.8 Hertz     one leg    total 7750W   moderate smoke. heavy load no rpm loss

Question How do the numbers look on this test?
 
 The gen voltage seems to be getting more stable with run time.

At 7500W I put a contact pyrometer on the head fins and recorded a 218F temp after 5 minutes of running at this load. I will try this test again with a laser pyrometer on the exhaust/manifold next week.

 With the 7500W load on it I manually increased the rack to bring the hertz up and the RPMs increased but with Heavy smoke.  At that point I thought the air cleaner was restricting the engine/intake but there was no reduction of smoke when I removed it. I think the engine is turning above 3600RPM. I also think it is just running out of cam at this point.
W.O.T. LINKAGE NO LOAD I tried to increase the RPMs and the engine smoked immediately upon rack increase. I think that I will order the lower ratio pullies.I think if I can slow the engine down and get it back up higher on its torque curve it will carry more load at the desired Gen head RPM. I also think that once the engine breaks in it may do better, but at this point it only has 2 hours of no load run time.

CAN YOU SAY TURBO CHARGED!
I work three jobs, one full time and two fun part time jobs. The reason I'm mentioning it is the fact that I work on a professional NHRA drag team and we are always trying to get another tenth or MPH out of the car, hence my need to not leave well enough alone.   
 
 Thank you all again for your help and expertise in answering my remedial questions.

Bluecometk.

I am building a back-up Generator using a 10HP @ 3600 RPM Yanmar diesel and a Chinese ST type 8 KW  @1800 RPM Gen head. I have a Gates PowerGrip GT 2 Sprocket drive belt and sprocket system which is roughly 2 to 1(Drive/Driven)
Drive size 2.206/Driven 4.411. I have been building it for about 3 months on the weekends. What's taking so long is #1 I'm slow at building stuff, #2 Roller frame, custom gen/belt screw adjuster, battery box, tank over Gen head   mount, noise/ weather enclosure and onboard electric panel/control panel, #3 interruptions from honey dew list!

I'm fabricating everything first and trying it out, then I will tear it apart and paint/powder coat it all. At that time, I will take the Gen head apart and perform all of the tips and modifications I have learned from the forum and order the Utterpower CD and rectifier kit.

Today was first start up day. Engine, Gen, drive system, frame, just to make sure my theory worked. Well, it didn't go as planned. According to the engine manufacturer the linkage is set for 3600 RPM @ the linkage W.O.T. position. I have no real way to tell if it attained that RPM yet. I was going to use the generator voltage output, but that was only going up to 236 volts and it was wavering at that rate. I then put a makeshift 4 position 120v receptacle on the side of the gen head and plugged in 4200 Watts and the voltage went down to 100v on that leg. The engine hardly even changed notes and the rack arm moved open about a 1/32 of an inch. I don't think the engine was even laboring at all.

Now to the questions.
  Do you think I need to spin the head faster?

  Do you think I made a valid test by only using 1 leg of the gen @ 120V and not both legs and spreading the 4220 Watt       
   load out on 2 separate recepticals/120V legs?

 With the feeble attempt at information I gave you, can you determine if I can lower my engine rpm (10hp@ 3600/9HP@3000RPM) while increasing my Gen head rpm if needed? Ratio/sprocket changes are not a problem just expensive.

1.899 to 1    gen rpm 1800   engine RPM  3402
                               1,900                      3,591

1.759  to 1    gen rpm 1,800     eng RPM   3,166
                                1,900                      3,342

1.691 to 1    Gen rpm 1,800     eng RPM   3,042
                                1,900                      3,211

With the info above, if I run the Gen head at a projected target speed of 1850 rpm to attain my loaded voltage, will I have enough horsepower to get the rated 8KW with the ratios I have given you?
The engineer at Gates thinks I should be able to run it at the 1.691 ratio and still have 1.5 to 2.0 HP in reserve. What do you think? He had never been asked this type of generator drive system question before and was only venturing a guess.
He also said that the sprocket system I have has an extremely low parasitic HP draw on the engine.

Thank you in advance for any assistance you may be able to give me, it will be much appreciated!!

Bluecometk