More lake testing today........

[Arizona Hotboater]

Well, I did the small prop test and I swapped the center hub from another flywheel in case the magnets were going bad. Also, any of you YT dudes running 6" of setback may want to add 4 more. Heres an excerpt from an e-mail I sent to several people.

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I tried the hub from my friends used flywheel and his 22" small ear (inline 6) chopper.

No change. The plugs still only color slightly and I got a best of 76mph on GPS at 7000 with only me in the boat. It will rev freely with the 22" to 6000. Then more trim needs to be applied and will go to 64-6500. More trim and hold it wide open and it will inch to 6800. More waiting and a bit more trim got me 7000, finally. It didnt want to go that high, just didnt have the power to turn that little 22 chopper. I hit 74 mph @ 6500 last week with my 26 yamaha drag and 2 people in the boat. Last year I got 81 @ 7000 with the yamaha.

The volt meter doesnt go to 18 volts anymore. reads 12 with the motor off and about 14 at WOT. I think its time for a NEW stator, switchboxes, trigger, and rectifier.

By the way, the park plug coloration moves around. that is, the top cylinders are usually darkest but not always. Sometimes the middle or bottom plugs get darkest but none are really dark.

On a good note, the 4" setback spacers made the boat ride much better. Less trim is needed but the main benefit is that I dont have to cut the throttle back everytime I pass over a 1' wave. Much more stable.
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AZH

[Arizona Hotboater]

I got to thinking about prop slip and it didnt add up. Ran these figures on the prop slip computor and came up with 2% slip. Something is amiss. Either my buddies worked 22 inline 6 chopper is no longer a 22, or my tach is reading low. Since the prop performed similarly to my 26 yamaha drag, I think the prop has greater pitch than what is shown on the hub numbers. Cup looks normal for a chopper.
Hmmmmmm
AZH

[jimmyb]

depending on the work done on your prop, it might have some cup, which allows you to add +1" to your pitch.

Remember pitch numbers on the prop arent gospel truth, but an indication of speed/rpms you can expect from the prop.

people get too bent out of shape when doing the prop calculations... :) remember that the prop calculations is just a tool to see if you are in the right "ball park" with your setup and prop.

[Techno]

I remember that you changed quite a bit of that before.
What haven't you done/checked?
What have you done/checked?

Also for anyone new to this post, he origanly had a power/speed loss that led him down this road.

I you sure you don't have barnicles on the hull???:D

[Arizona Hotboater]

Techno,
I have replaced the stator with a used stator, installed 1 used switchbox, ran the motor with the bias circuit disconnected, replaced crank end seals, rebuilt the carbs, swapped carb locations, changed spark plugs, swapped coils around to different locations, ran a DVA / fluke meter on stator, trigger, and switchboxes, I found a water leak in the exhaust divider and fixed it. The leak happened after the motor was already down on power. The repair brought it back up to where it was before the leak but not up to par. I reset the reeds that were bowing out from over torquing. They close now but it made no difference. I made sure there is no water in the fuel, I dismantled the front half to check sealing rings, I richened the jets from 80's and 78's to 82's and 80's, I leaned the jets to 72's and 76's, I did a fuel pressure check at idle, mid, and WOT....6.2 psi always, I held in the fuel enrichment while at WOT. That didnt even color the plugs, but it lost 3-400 rpm from being over rich. When I tried it again with the leaner jets it had no effect indicating they were then too lean. I sprayed starting fluid around the engine to check for vacuum leaks...none. I verified no checkballs / obstructions. I charged my battery. I had a friend spray fogging oil (which has a fuel in it) in each venturi while at wide open throttle, it lost 300 rpm each time indicating it was not running lean and all carbs were running evenly. Not even that made the plugs color. There was no color change in the plugs between 82's / 80's and 76's / 72's! 2 plugs color up a bit, 2 have a wisp of color, and 2 are white after a full throttle shut down. I pressure tested the block for water leaks with a tester Greg Moss sent me, I did a compression check. 143lbs to 149lbs. I changed the lower unit oil and made certain it was not malfunctioning. It has to be something in the ignition. I just bought a new stator, trigger, rectifier and switch boxes. All are Rapair/CDI. Was going to get them from Rickracer, he had a great price on 'em, but a friend of a friend has a mobile marine service and got them for me at cost. (Sorry Rick, too good to pass up.) I will bolt these on this weekend and cross my fingers. Boat will accellerate great, just wont get the top speed it used to and wont color the plugs. This motor has maybe 35 hrs on it since complete rebuild and used to color the plugs fine. STRANGE!
Any thoughts?
Marc AZH :(

[WillyT]

Since you are obviously looking for any ideas, I will throw a wild one at you. This does not address your plug color issue, but does address the speed issue. A guru at Mercury once told me that many boats will lose speed over time due to the development of a hook in the boat that is there ONLY while the boat is UNDER LOAD (i.e., while at speed). As the boat ages, and as the bottom becomes just a little softer from being in the water, the bottom will "bend" (hook) while underway simply due to the force of the prop/engine pushing against the transom. This hook will typically disappear when you look at the boat on the trailer. The Merc guy says he has frequently seen new boats lose several mph from the beginning of the season to the end of the season for this single reason. When the hull "dries out" over the winter, some speed may return in the spring (at first, at least). Such a hook would probably help acceleration/hole shot, but would hurt top end. I wonder if others on this board have ever noticed a slight degredation in speed over time and could not figure out why? In some cases, as you know, a PERMANENT hook may develop that CAN be seen on the trailer. Have you placed a straight edge on your running surfaces lately (especially the middle sponson near the rear)? On a tunnel, the boat trailer normally does not support the transom right below the engine. Have your trailing edges become rounded instead of sharp from beaching the boat (or whatever?) Are your props still as "pristine" as they were the last time you used them (I've discovered that the tiniest ding will cost several mph). Lastly, have you gained 15 pounds of muscle from lifting that engine (lol)? Weight really does hurt tunnels, you know. Just some "out of the box" thoughts. Let us know the results of the new electrical parts. Good luck.

[daytona]

Hi AZ This is probably stupid but the last time I chased one of these unsolvable problems it turned out to be that my tuner had fallen off and and was stuck in the mid restricting the exhaust. good luck, rick

[Arizona Hotboater]

Thanks guys, but tuner is in place and no hook in the bottom. My boat was one of the botched jobs that Hydrostream did. It got a saturated core and had to be rebuilt in 1990. That transom, floor and bottom are as hard and straight as nails. What ever is causing this is linked to the plug coloration. I will keep everyone informed. As for my weight, I'm 210, down from 218, and in Dallas when I first rode on the boat, it went 86 with 2 of us in it. I know I will loose some speed from altitude here in Phoenix, but it ran over 80 here last year. As the problem got worse, so did the plug color. Hmmmmmmm And Techno, No barnicles in Phoenix. Well, there was this girl I dated once, and......
Thanks,
AZH

[all8up]

try changing BOTH switchboxes!

[Arizona Hotboater]

Yep,
already ordered them my friend. Everything in my motor is new except the electronics. If this doesnt fix it.... well,.... then I will have new everything. The only reason I changed only 1 box is thats all I could borrow. I disconnected the bias circuit and thought that would isolate the boxes. I dunno. We will see and I will keep everyone posted.
Marc AZH

[Ron V]

Marc,

WillyT hit something that I was wondering may be your problem. If you recall, StandPat had a similar problem because of a "power-induced" hook in a Hydrostream. I think it may have even been a Valero, and it had sat for some years. He diagnosed it by putting a 4 x 4 on end on a floor jack and jacking up the keel of the boat on the trailer. The hull hooked without lifting the boat up. That was when he knew the bottom was rotted inside. Memory seems to tell me that he hit a brick wall at 75 mph (just like you) when it had run just over 80 in prior years (just like you). He had put a new motor on it and couldn't figure out how it could be slower with a newer motor with a more honest horsepower rating. Fixed it and it got right up and ran 85 mph or something like that.

The other red flag? Used electrical parts. Having read everything, I'd guess that if it is indeed a motor problem, the used stator was not good. I don't know much about ignition systems and electrical parts, but a used stator, or a used ANYTHING would be a red flag to me if I went out and it didn't run right afterward. Your original stator may have been bad and then by a stroke of bad luck the used one you got to replace it had the same problem?

Ron

[Arizona Hotboater]

Ron,
there is no problem with my hull. I checked that too. Gotta be electrical. As for the used stator, I never gave the shop permission to put in a used one. I wish they had installed a new one. But it checks out fine on the DVA and there was no change after replacement other that clearing up the volt meter output problem. I thought there was an improvement in performance but it turned out to be water conditions were more favorable. The used stator may be bad...thats why I'm replacing it also, but it does generate the power to run the ignition. I feel the problem is in the switchboxes or trigger. I will know as soon as I bolt on the parts and lake test again. Stay tuned to this station for more on this story.
See ya,
Marc