How many hours does it take to fill them up? I have had 3 15s and a 17 all KAI and they have done very well, blowing the fins out once per season works great -- with compressed air without taking the metal covers off. Probably run them 400-500 hours per season.

 

Mine had a leaky top oil seal--the oil will cause grass to stick to the fins.

 

I don't know that Kawa is the only engine with this problem, every manual says to take 'em apart at 150 hour intervals,and clean 'em, course nobody does it, and the result is as you described. I, have for years, once the engines come in, pull off all the tin shield baffles, (shrouds) and send 'em out, cause what is the purpose of having the shroud if it is plugged with crud, or making it easier to blow them out with a blowgun and no shroud. I have done it on Onan,Briggs, Kawa,Kohler, you name it, clean = cool, Deutz learned this lesson on air cooled diesels in North Africa along time ago, if it's air cooled, air flow is critical, especially on tanks.

 

they should be cleaned out often anyway depending on where and what u do , kawi usually drop a valve guide when they over heat which then causes then to bend pushrods

 

Its best to stay on top of it by blowing them out often. When grass catches in the fins its easy for more grass to quickly pack against it. Use a bent nozzle air gun so you can go up under the cylinders. Blow in ever nook and opening you can. Do it with the engine off and do it with the engine running. Just don’t poke the nozzle into the flywheel. The shroud is designed to be easily removed. The bolts only need to be loosened not removed to pull the shroud. Like others have said, when it starts to leak oil its worse. The top main bearing gets loose after high hours or not enough oil changes. The breather gaskets also get brittle and leak. You will get the longest engine life with frequent oil changes and cooling system cleaning. Leave the shrouds on. The hottest spots are not at the outside edges of the fins. The hot spots are around the valves and exhaust ports. The shrouds keep the air from dissipating too quickly. They want the air funneled so to speak so it can remove the heat. Its most likely that they had it figured out how to direct the air. If they could have saved a dime by not needing them I will guarantee they wouldn’t be on there.

 

As Kiall1987 said they will drop valve guides when overheated. There is a way to fix the cylinder heads. It can even be done without pulling the head.

 

I have a 19hp Kaw, vertical shaft engine. A few times per week, I use my Stihl hand blower against every nook and cranny, while the engine is running. And, once per week, use compressed air to blow out what I can under the shroud.

At season end, I pull off the shrouds, and have never found any debris in the fins. As somebody said above, keep after the cleaning on a regular basis, not allowing the debris to build up.

 

As Kiall1987 said they will drop valve guides when overheated. There is a way to fix the cylinder heads. It can even be done without pulling the head.

Please describe this process. I just had a customers engine come in - both heads had overheated and dropped the guides - bending the push rods. I had to pull both heads. As I understand it, once those guides go, you pretty much have to get another head - as they are pressed in and not available separately. If you just push them back in, you run the risk of throwing the valve guide again real soon.

 

I don't know that Kawa is the only engine with this problem, every manual says to take 'em apart at 150 hour intervals,and clean 'em, course nobody does it, and the result is as you described. I, have for years, once the engines come in, pull off all the tin shield baffles, (shrouds) and send 'em out, cause what is the purpose of having the shroud if it is plugged with crud, or making it easier to blow them out with a blowgun and no shroud. I have done it on Onan,Briggs, Kawa,Kohler, you name it, clean = cool, Deutz learned this lesson on air cooled diesels in North Africa along time ago, if it's air cooled, air flow is critical, especially on tanks.

The shrouds are necessary to keep the forced air from the flywheel fan moving over the fins, allowing for heat transfer. Otherwise, without the air movement, as soon as the air envelope around the engine heats up, there is very little cooling going on.

 

Please describe this process. I just had a customers engine come in - both heads had overheated and dropped the guides - bending the push rods. I had to pull both heads. As I understand it, once those guides go, you pretty much have to get another head - as they are pressed in and not available separately. If you just push them back in, you run the risk of throwing the valve guide again real soon.

Push the guide back in to the proper dept. Be sure its right so the seal fits correctly. Then you drill, tap and install a set screw to hold the guide. I don't have a photo of it right now but you need to eye ball it an find an area that lets you drill into the guide. Double set screw it with loctite. I have done it without taking the head off. The tip of the drill will touch the valve but the valve is so hard it wont cut it. At that point the drill hasn't gone all the way through. The point of the drill has touched the valve. Now tap the hole all the way down in. Your not trying to go real tight against the valve, just enough to let the set screw act as a key and hold the guide in place. Then lock another set screw against it. I have done them off the engine with the valves out and the tip of the drill breaks through the inner wall of the guide but it wont hurt anything. Obviously you don't want the set screw to protrude into the hole or the valve will rub on it. I will try to get a photo of the spot that I drilled. Maybe tomorrow.

 

Good idea - I never thought of drilling into the valve guide seat and then putting in a hex-head to lock it in. That's very innovative. I like it - certainly saves on buying a new head. Thanks for the tip!