Where did you get the barrel

Making progress but slow. I have finished the inlet tubing and the outlets are finished. All that's left is cut out my can end caps and start welding the pieces together. The outlets will go 3" into the 4" can and the holes will face each other so I have some back pressure. Each tube has nine 3/8" holes so it should breath, I think?? Quite, who knows?

Looks great, "back pressure" is used falsely. Exhaust is rhythmic and getting the pulses right is what tunes the exhaust. Your design looks good and the number of holes should be sufficient for flow. The sound is all on acoustics within the system. If you can, make some baffles within the can itself or make the end caps double wall. A screen or perforated inner with with steel wool between it and the outer. That will dampen the high pitched waves and create a lower, cleaner sound.

The carbon shouldn't effect it, the steel wool is cancelling sound waves is all. An acoustical blanket if you will. That's how the straight through mufflers work, high flow exhaust but cancelling out certain sound waves to alter the sound. An empty can has an empty, pingy sound... Get rid of those high frequencies and its nice and low.

Muffler is finished, all that's left is make a bracket for the tach. Trying to put it next to the control box, as with these old eyes I'll see it better. I followed Will's suggestion and added some SS cleaning pad fill. I also followed (sort of) what Lee did for extra support for the muffler.

Great looking work on that muffler. I'll be interested to hear if there's anything you'd change after running it a bit.

I'll draw something up in the morning, I mentioned double wall. I'm not sure it will work if you have the gases trying to find their way through the mesh. The "gases" need and open flow, everything else is to cancel sound waves... And empty can is pingy, baffles distort sound, steel mesh absorbs sound, fiberglass mesh absorbs more sound of different frequencies. Look up "muffler packing" til then.

This is similar to what I believe will allow enough flow and have a low, quiet tone.

I understand your thoughts on this and appreciate the drawing. I no doubt will start the engine with what I have now, but have printed the sketch for the future. Thank you, Wayne

Found a picture of how the unit was rigged onto the boat on page 33. My question is did you all just lift it with the factory thin assed lifting eyes? I used them to set the engine on the lower while on the stand but was thinking maybe more rigging was needed for the weight of the whole unit? I have a large 1940s cherry picker and engine spreader bar so that part is handled. and a good deal of slings. Thanks much, as I want to hang it this Tuesday and if I can get by without extra, it will be easier on this old guy.

Yes, the factory lifting eyes will support it all. GTR, PD, etc.. they all lift by those.

Folks after all that work, IT LIVES! Got back from my VA appointment early enough, and the rain stopped. I finished up right after lunch and fired it up. The muffler sounds great, but I wont really know till I bring the revs way up. I was just in the start mode and will put some time on it before I start bringing up the rpms.
I have some questions on the idle speed. If I remember right Lee said if you idle down too far the compression release kicks in. So is the idle set by the carb stop screw, or on the left side top,or bottom screw? I'm very happy right now just wish I were younger and still shooting ducks or if it was above the 35* so I could head out into the bay.
I thank all for their help so far.
Wayne

Great job man! I recently HAD to build another pipe as the old one plumb rotted out. My intention was to go with a four inch can but wound up using 3" because it was on hand. The pics are prior to bracing.

Seems like that stock carb needed to be a tad high 1200'ish to maintain the loaded idle above about 750-800 or the comp. release would start working and it'd try to die. There's a really finicky adjustment to the governor arms that makes all the difference in the world. There's a 10mm bolt holding the two arms together and you'll wanna loosen it JUST ENOUGH to be able to move the arms, it's sorta a cam action. If they're too loose it'll rev WIDE OPEN HARD. That adjustment is critical to getting the lower idle rpm that'll stay just above the CR starting to work.

This'n is done now I just hafta see how it runs! Got lucky and reused the old bracing with minor modifications. Got a sweet tone!

The next time one of the kawasaki crew has their flywheel pulled for a cam change I could use a picture of both sides of the flywheel. I'm thinking about making an emergency only start pulley that could be bolted on if one loses either the starter or not enough battery power.
I had it on my 96 GD LT and it came to good use once, which was worth the $50 extra cost.

WE have already looked into this, but you have to keep the stock cam with the compression release. The 4 bolt holes on top of the flywheel will allow you to have an adapter machined and bolt straight to the flywheel. The compression release built into the stock cam will allow you to pull start the motor. I removed the grass screen off of mine and removed about 1lb of weight off the flywheel by doing that. You can simply add your adapter and pulley and it would be under the outer screen for protection. Simply remove the outer screens 3 bolts and wrap on your rope. but then youll have a pulley spinning about 1200 rpms while you put your screen back on. We looked into this for emergency purposes only, but when we went to the cam, all bets were off. You were not going to pull start 180 psi of compression with no release.

IMG_3158.JPG

It was going to use the 4 bolt holes you see. That's my homemade flywheel puller., but you see you have a flat surface for the adapter to bolt to.

What else you need.

I figured I'd post a li'l update for those that give a toot... The new muffler design is bad azz, seems to run as well as any of the "two into one" pipes I've built and has a nicer deeper tone. It should be pretty durable too, but I've got a piece of 4" SS pipe on the way to build a Mo' better one. I've found that although the 3" can may possibly have a couple advantages (it was built this way out of necessity) it's a real pain in the the butt to get the baffles welded in like I wanted. This effectively left a larger chamber on both sides of the outlet than i wanted and allows a certain harsh tone to be heard at specific angles to the outlet. I think this can be cured by recessing and lengthening the outlet pipe...

Bump for Boudreaux

I know this has been dormant for a while but today was actually the first day I got out on the boat. Everything I had done worked fine in the driveway as I finished it during the winter. There were three of us and the torque was a big improvement as my boat went to step quickly and picked up a few mph. So now the problems that really have me pissed. Once I clear the ramp area I punch it and am running at about 3720 rpm, but when I went to slow down I was stuck at full throttle. Killed it and thought I broke my S.S. cable, not the case the factory arm (2 screw area) attached to the governor spring needed a push to return my throttle cable and the carb to the idle position. Even now in the driveway if I twist the grip not running it sticks wide open. The engine was idling under load at around 1250 rpm and pushed the boat just under 5 mph. That is the big issue, but there is another that is very strange. When I'm under load and want to slowly increase my speed it seems like the engine is "hunting" for an rpm. So it isn't holding a mid range rpm, not what I'm used to.
Please any and all input would be appreciated, and the exhaust I built sounds great and not as loud as I was worried about.

Get a mikuni. The hunting is probably the governor assembly on the cam. the spider with all the ball bearing. Remove all that crap and you should be fine.

^ I concur


You can probably rig up a return spring for the throttle.

I'm Pretty sure Owen ran a stock carb on his for a little while. The "hunting" definitely sounds like some type of governor issue, but if you can reach top rpm's and it doesn't really cause any performance issues, I'm not sure I would sweat it all that much. Not sure how much he's on here anymore, but I'm not sure if anyone else used the stock carb even for a short time. You could reach out to him via pm or I think his phone number is on PD's website. He used to be an authorized service center. I'm assuming he still is.

Owen hasn't reached out to me yet, but another question on the governor? I read here on a search about the tie wrap mod on the governor spring. Might that help my surging / hunting issue? What did that do?
Thanks all, Wayne

The tie wrap allows you to basically negate some of the effect the governor has on you spinning the motor higher rpms. It allows you squeezing the throttle to fight the governor wanting to throttle down with a larger effect. On my smaller kawa, I couldn't set the idle low enough and still spin my motor up to max in water rpms without the tie wrap after my mods. It was either idle at 2k and spin to 4300 in water, or idle at 1350 and spin to 4k.

Edit: It can be dangerous out of water, though, because the governor may not be able to keep you from over revving the engine. Keep that in the back of your mind.
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With these you've got a two piece governor arm that actually has a cam in the middle. When I ran the stock carb initially I found out quick that you must adjust the attitude of the governor arms to each other or you'll wind up not reaching full throttle or low idle. With a stock cam the idle needs to stay above 850'ish PRMs or the compression release will start functioning and it won't stay running. This is a trial and error type adjustment and I'd recommend you back the hold down bolt out barely enough to move the arms because anymore than that and it'll immediately scream to wide open in your face! It's a fairly tricky little adjustment but once you've found the sweet spot it's the best governor I've ever seen on a mudmotor.