Hey you guys, I have been reading and reading on here as well as the service manual and I'm still not understanding how to (or even if I can) adjust my rpm under load.

OOW I turn between 4150-4200. In water with me in the boat, nothing else I'm turning 3400 (if I'm lucky). With the girl, kid, dog (another 225#) I'm turning 3360. I'm currently running a rebuilt 9x6 prop that is NOT even 9" so i'm not concerned with my speed at this point. I would however expect over 3600 rpm, and in a perfect world even close to 4K.

I have adusted the cav plate to run as close to surface as possible. I can't help but feel i'm leaving some rpm on the table.

boat is a 15x44 legendcraft with pods. It's welded, has a floor and gun box but still I would think well within the comfortable range of a 27.

I'm sure the springs are not attached as per stock so I'll try to post a picture.

Thanks in advance for thoughts, suggestions, or even outbursts

J.

If you can turn 41-42 out of water then you can turn it in the water too. Your motor just doesn't have the power to do it. Not sure on what the appropriate prop is, but it could be over propped. What kind of speed are you getting?

You may try doing a compression check, followed by a leak down if compression is not normal.

picture of possible disaster that is my motor.

Your linkage looks fine. You may pull the air filter off and look at the butterfly on the carb, just to make sure you are getting full travel. Also make sure your choke is not closing on it's own and that it is fully open when it's supposed to be.

Thanks for the tip, cb. I will do that. I was hoping you would notice my post.

Choke appears to be fully open and butterfly is vertical. Actually it barely closes when I close the throttle. when I push the governor arm over it does close.

I did however notice the rubber tube (the one that comes up through the filter plate) is 90% ripped across just above the hose clamp. I'm not exactly sure what this does but I wonder if this affects performance. Regardless, I'll have to order a new one. thoughts?

pic of carb.

That lil hose is just a breather. It dumps any residual oil that is blown out back down in to the carb to be burned off. Emissions crap, not a big deal. Replacing it is not a bad idea, but it isn't hurting anything. Worst case scenario, it is letting a lil oil drip down on the case instead of back through the carb.

When the motor is not running, a lot of times there isn't enough pressure to close the butterfly when you release the throttle. When it's running it will close. Sounds like all that stuff is good.

Try to do a compression check if possible. If you don't have a tester, most auto parts stores will let you rent one. Just have to put a deposit down, but doesn't cost anything. Looking for uniformity between the cylinders more so than a specific number. Somewhere in the 150psi range should be good though. Make sure you do the test with the throttle wide open. If the compression test doesn't pan out, we'll try to get you to do a leak down to find out where you are loosing pressure. If the comp test checks out and the cylinders are close to each other, I'd say the motor is fine. That's just all she's got.

Main thing to remember is this is a long tail so you're not able to trim the motor up and run the prop on the surface. All your prop is under the water so you won't be able to turn near the rpms in the water as out of the water.

Hmmm, so it's 135/135 psi (edit: forgot to leave throttle open so will redo tomorrow but doesn't look like it's a problem). Not good news for performance this fall but possibly good news for my pocket book, Unless i decide to add some more grunt.

bbb, yeah... you are right. In my reading it just seems the difference I am seeing is a lot more than others. I guess I could restrict my top rpm to reduce that difference and make me feel better. Still would be 3400 in the water though. I guy should be happy it starts and runs pretty good and is reliable I suppose.

If that's all she's got, where would I start if I wanted to grab 400 rpm? Exhaust? Heads?
Is gutting the muffler usefull or just something that makes us feel good?

She is 9 years old so I should have a plan for when it gets rebuilt.

You may try a slightly smaller prop. That could get your rpm's up a lil bit. What kind of speed are you getting? Does it seem to be running okay? Didn't seem to bog down too much with a little more load than just you by yourself, so I wouldn't think the prop was way too big.

Compression numbers sound good. Try again with the throttle open, but both cylinders being dead on even is good. Especially for a 9 year old motor.

You can get the 30hp heads off of ebay for about 250 bucks. It's a good lil boost in power. BPS has the Q muffler. Gutting the stock exhaust will help too if you don't wanna spring for the aftermarket one. Gonna give you more bottom end than top end, but it'll be a noticeable increase in power for sure. Also velocity stack and k&n filter will free up the air going in to the carb and is a good idea IMO if you are gonna go forward with the heads and exhaust.

Also, no reason to change your out of water rpm's. Turning them down is not going to help anything, and leaving them where they are is not gonna hurt anything.

It runs strong @ 16.7 mph all day long with me (170#), the girlfriend (120#), kid (40#), and dog (50#).

18.1 mph alone.

I do have a welder and would be very interested in gutting the muffler as a project. In my reading heads sound like a wise performance investment.

sounds like your motor is running great...my 27 kohler will hit 19 mph with 2 people, just listen to bbb and cb!!

Yup, you're right. I wasn't as concerned with my speed as much as my rpm. Understandably my speed would increase when I got my rpm back up.

I've had a long tail since 1999, bought a 23 from warren (LSU grad down from Canada), then a 25 after I sold the 23 up here. Then built the 27 as it was the 'big dog' at the time. Honestly, the 27 has been the slowest of the bunch. My buddy still runs my 23 and iirc I would go 21 alone in the same boat. I know I was running more rpm on both the 23 and 25.

anhoo... It's still summer and I have a bit of time so I thought I would poke around and see if my 27 was set up properly as I had leant it to a buddy to guide for moose the last couple years.

Maybe a surface drive is in my future... maybe. I cant help but think I would go back to a 23 as I did love that little motor. Then again, I did see a 35 for $2000 at the local store (harbour freight equivalent). I guy needs a project on the go at all times right?