Tried a hydrofoil, and decarbed today-interesting results

[JasonJ]

I have usually been more for trim tabs than hydrofoils, I think trim tabs are a better way to get it done, but the guy who is renting the other side of my dock from me put on an interesting hydrofoil. His buddy put the same kind on his boat as well. These guys could not say anything bad about the thing, and these are new-ish boats, one a Chaparell and the other a Chris Craft. Since my boat is old, skanky, and has no power trim to speak of, I thought I would try this thing out. It is an Attwood plastic two piece job that is more of a gullwing configuration. They stick up at angles, the theory being that once on plane, less of the surface is in or touching water, reducing top end speed robbing that flat foils cause. I was a bit skeptical, but $32 isn't a lot to spend on an experiment. My rig has always taken a little bit to get on plane, but when I am by myself it never bothers me. When I have other people in, it is noticeably more difficult to get on plane. It took ten minutes to install them, once complete I did my decarbing.<br /><br /> Put Seafoam in 3/4 gallon of gas/oil mix, and ran the outboard at 3000 rpms until it was all gone. It was a smoky, stinky ordeal, but it was interesting. The first half of my brew burned pretty quick, but as the motor was running, it started taking longer for the second half to burn off. Rpms staying the same at 3000, it took almost three times as long for the second half of my brew to burn off as it did the first half. I also noticed that the motor quieted down a good bit. Once complete, it was time to take it out for a test run.<br /><br />The engine ran noticeably smoother, less shake, and not as noisy as I idled out to the lake. Once I attempted to go on plane, the boat went on plane dramatically quicker, and with less throttle. Usually I floor it to get on plane, then bring it back to 4000 rpms for cruising. I deliberatly only brought it up to 4000 and it went up on plane very quickly and rpms climbed. I can stay on plane at a slower speed, but that wasn't what I was looking for. Top speed is the same as it was before, the foil is not leaching anything. The boat turns differently now, the stern doesn't want to burry itself like it did, which I actually liked that, it felt more secure. Now, because of the lifting of the foil, it does not squat in tight turns, but it still turns sharply and leans very well, like it should. The decarb didn't increase the power (I didn't expect it to), but it did make the motor more quiet, and it was smoother and sounded better at any rpm. It was a healthy 35 year old engine before, now it is better. Just thought I would share my foil/decarb day...

 

[cobra 3.0]

Re: Tried a hydrofoil, and decarbed today-interesting results

I've noticed the same with a Stingray hydrofoil...except it did rob about 2 mph off top end. And since mine is an I/O I couldn't play with motor heigtht and suspect the foil is too low and causing too much lift, robbing from top end. I'd be curious to try this V type foil.

 

[tmcalavy]

Re: Tried a hydrofoil, and decarbed today-interesting results

Jason,<br />Is your hydrofoil the type where the wings sweep forward? I've seen ads for these but always thought someone in the advertising/art dept. drew it in wrong, as the wings go forward instead of looking like the traditional whale tail foils. I need to decarb my old 73 Merc 500...will probably follow the example you set with hopefully the same results.

 

[JasonJ]

Re: Tried a hydrofoil, and decarbed today-interesting results

Tim, they have the one I bought here in the Iboats Mega Mall. Just type in Attwood Hydro-stabilizer in the search function. The wings sweep up. For the price, they work pretty good. I had figured on just returning them if they did not work, but my skepticism was set asside.<br /><br />I only did one phase of the decarb. The other phase would be to pull plugs, spray generous amounts throught the holes, and let soak for 6 or so hours, but my motor was not that bad, It had good even compression, I just wanted to do it just to do it, and it made things better.

 

[MarkAB]

Re: Tried a hydrofoil, and decarbed today-interesting results

Jason, is Seafoam a cleaning agent? Never heard of it in SA before.

 

[phatmanmike]

Re: Tried a hydrofoil, and decarbed today-interesting results

sea foam here at iboats.com

 

[Jdeagro]

Re: Tried a hydrofoil, and decarbed today-interesting results

Jason;<br /><br />Don't kid your self about how much extra power you get from decarbing the engine. The reason the engine did not run smoothly at low RPM's before is that there was a loss in compression to to the carbon build up. This also affects to speed as well, it is not as noticeable because as the engine speed increases the misfiring happens so quickly. Try running the boat without the foil now and see if your top speed is better.<br /><br />You should never change two things at one time and test. It just confuses the outcome.

 

[JasonJ]

Re: Tried a hydrofoil, and decarbed today-interesting results

Yeah, I know all about testing after doing two things, but I was impatient, you know how that goes. Plus, like I had said, the motor never ran poorly, it just sounds and feels smoother now, about what I expected from the process. I had 120-ish psi before the decarb, not bad for a 35 year old motor. Top speed has never been an issue, I never run wide open except on that rare occasion that I get a wild hair, and then it is for less than a minute. The foil will suffice until I decide tabs are a must, or I get another project.

 

[Jdeagro]

Re: Tried a hydrofoil, and decarbed today-interesting results

I spent 35 years in the Automotive market, and 11 years as a consultant. One of my clients was Chevron (Techron - additive) and It is amazing what a decarb will do to improve the running of any motor. <br /><br />I get impatient myself.

 

[crab bait]

Re: Tried a hydrofoil, and decarbed today-interesting results

yeah, ain't it great..!!<br /><br />you reap so much benifit it's mind blowin'..<br /><br />it's almost ( an it would be almost worth it ) like you spent $ 15 hundred bucs on an engine soup ditty.. but only spent 35 .. ain't it great..<br /><br />they sure do work..

 

[sangerwaker]

Re: Tried a hydrofoil, and decarbed today-interesting results

I decarboned my '97 Merc 200 EFI on Sunday and noticed similar results. Soother idle, and less smoke. I did not notice any difference in top end. It also runs a lot quieter now, too. I used the 3/4 gallon gas and Seafoam mix as well. Worked great and a LOT less expensive than other products/methods I have used.

 

[wallbanger2]

Re: Tried a hydrofoil, and decarbed today-interesting results

JasonJ, you mentioned that it took alot longer to burn the second half of your decarb solution. Did you notice if you picked up any fuel ecconomy after the decarbing?

 

[JasonJ]

Re: Tried a hydrofoil, and decarbed today-interesting results

Wallbanger2, it is hard to say. I did a long run yesterday to get to a fishin' area, burned about the same as usual, but the difference was the water is normally calm and I never run it wide open, but yesterday the water was pretty rough, about 1 to 1.5 foot swells and heavy chop with about a 15 mph headwind most of the way. I also ran it wide open in the wind shadows, just for giggles. I think it is fair to say that I am probably getting better fuel economy now considering the above statement, but the problem, as Nautijohn pointed out, is I put the foil on and decarbed, so unless I remove the foil, run some numbers, and put it back on and run numbers, it will be hard to say what has actually given me the improvements.

 

[Mark42]

Re: Tried a hydrofoil, and decarbed today-interesting results

Jason,<br /><br />I tried the hydrofoil too. I liked the improvement in handling it gave. But after adjusting the trim bolt all the way in (mine has only three holes) the boat handled better than with the foil. <br /><br />I would suggest that if you liked some of the improvement of the foil, then trim in somemore and run without it.