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motor tuneing

Old 08-31-2008, 09:00 AM
  #26  
kwiktsi
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Default RE: motor tuneing

ORIGINAL: rocket-ron


ORIGINAL: kwiktsi

I was just messing with the carb on my blackjack to try to set the low speed by Tony's info and had no luck. With the needle anywhere near 1 1/2, it would not run and I never heard a "woowing" sound like he describes.]. I turned it in until it leaned and revved, then just until it was about to stall and then backed it out about 1/2 turn or so until it started running very rough and then kept going back and forth until I found a good midway point between the two- does that sound about right? I am running 6oz/gal and it is set so that it lets out the slightest bit of smoke at idle.

Now, with setting the high end- is it ever supposed to "clean out" and scream up top, or leave it so that it still has a slight "gurgle" to it? I have it a bit on the rich side so it never sounds like it is screaming, but it isn't sluggish either. I wonder if I can lean it a touch more without hurting things.
Does the boat run well at these settings? I'd be happy to get one tank of fuel through my Miss Elam,without it dying,or stalling on me. Ron
The boat runs great. The method above gave me a good starting point on my LSN, but I had to richen it up about 1/8-1/4 turn or so. The HSN, to me is fairly easy to tune- set it rich and lean it out as you go. Like others here have said- lean stalls, rich runs. I just backed it out until you can see and hear a noticeable drop in power, then turned it in while checking the plug every 6 laps or so until it looked perfect. Once I got it perfect, I backed it out ever so slightly just to give it a bit of cushion just in case and to help compensate for the tank running down.

The boat runs beautifully and will run through an entire tank without so much as a hiccup, pull it in, add more and keep going.

Keep in mind, tuning the boat out of the water is nothing like tuning your Zenoah planes. The motor in the plane has constant load on it (prop) and is easy to tune. The boat has no load when it it out of the water, so if you set it so it runs perfectly on the stand, it will be way too lean on the water. Like the guy above who mentioned setting his carb for max RPM on the stand- 1) it is going to be grossly lean on the water and 2) you really don't want to free rev an unloaded engine like that, you're looking to blow it up!

If the boat still seems too lean, even at the factory settings +1/4 or so, I would pull the carb off and check the screen. I have heard/read a lot about them being clogged with debris from assembly and such. Also, check the nipples on the tank- I have read about at least one being plugged with a piece of plastic.

The boat will run great, there is no reason to keep sending them back, you just keep starting back at square one when you do. Stick with one, give it a good once over and learn to tune it properly and you'll have a great running boat.
Old 08-31-2008, 11:05 AM
  #27  
RKS1949
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Thanks,kwiktsi ! I'll check out the screen (I didn't do that). I also noticed that the "pressure tap" on the intake block was installed with the tap pointing up. I think on the other boats it was pointing down. Don't think this makes any diffrence though. Ron
Old 08-31-2008, 01:11 PM
  #28  
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Default RE: motor tuneing


ORIGINAL: rocket-ron

Yeah,I like to run a Little "FAT" on all my motors. I'd just like to be able to get this one to run well period! So Far it's been launch,then retrieve,launch[:@] Ron
Carb settings will be a lot of trial and error. Settings will vary with temp and altitude as well as exhaust tuning. The standard carb is a 644 - the settings I used after the engine was broken in are Low 1 High 1 3/4 at 720 ft. above sea level 70-75 degrees.

Try these and if necessary fatten at 1/8 increments. If it's dying at launch, richen the low first. If it's dying while running at higher speeds, richen the high needle. Everyone plays the tow in by canoe till they get it right.
Old 08-31-2008, 02:34 PM
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Thanks,Proboat 772! I'll give that a try!Should I run the oil mix at 16:1 or 32:1 ? I think the settings would be diffrent,according to the fuel ratio. The boat owners manual,and Zenoah engine manual have diffrent specs,as to oil ratio,octane rating requirments,ect. It's very confusing for a new boat owner to figure out. Ron
Old 08-31-2008, 04:32 PM
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Proboat 772
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Default RE: motor tuneing

I would go with 8 oz of a quality synthetic oil / gallon reg gas ( 16:1). I use Zenoah synthetic oil and it works fine with no residue. There are many other brands that are excellent also. The richer mixture will give extra lubrication especially during break in.

I know there are many guys that have reported piston or ring problems ( seizing) but I have had none using this mix ratio with 3 stock engines. Maybe I've been lucky??

Dick T
Old 08-31-2008, 04:59 PM
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kwiktsi
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Default RE: motor tuneing

I have only ran about 4 tanks through mine, but I run it with 7oz/gal. I was told 6oz/gallon by several people, but read at least 8oz here, so I split it. I have spoken with others (including Zenoah and a few boat suppliers) who run Zenoahs in everything from planes to yard tools and they all basically laughed and said you are just wasting oil running it richer than the recommended 32:1, so I don't know who's right. I know the previous owner ran 6oz/gal with no issues, so I'm not too concerned about running 7. I have run it full throttle for pretty good stretches without a problem, if it were under-lubed, I'd have known it by now- I think- with my luck I just jinxed myself lol .

Either way, a little extra doesn't hurt- I just don't see the point in doubling the manufacturers suggested mixture.
Old 08-31-2008, 06:47 PM
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Default RE: motor tuneing



Either way, a little extra doesn't hurt- I just don't see the point in doubling the manufacturers suggested mixture.
Because a huge number of people have shown through long experience that the marine Zenoah engines perform better in the range of 6 to 10 ounces of oil per gallon. Especially a modded engine.

I run 8 ounces of Amsoil Dominator per gallon in my race engines. Works like a champ.
Old 08-31-2008, 06:59 PM
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ORIGINAL: Silent-AV8R



Either way, a little extra doesn't hurt- I just don't see the point in doubling the manufacturers suggested mixture.
Because a huge number of people have shown through long experience that the marine Zenoah engines perform better in the range of 6 to 10 ounces of oil per gallon. Especially a modded engine.

I run 8 ounces of Amsoil Dominator per gallon in my race engines. Works like a champ.
I don't disagree- especially with modded engines. I just don't think they need as much as some say- especially in stock form.
Old 08-31-2008, 08:53 PM
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RKS1949
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Default RE: motor tuneing

Thanks,guy's I think I'll just run 8 ounces per gallon. As Proboat mentioned,it's a( new motor) so a little extra can't hurt. I used Valvolene 2 stroke oil for the first gallon,and now I'm using Klotz Synthetic,the gallon I have premixed is at 16:1,but with 91 octane (manual specs again[:@]). I'll run that through the motor,then go to 87 octane,as that seems to be the most common octane used,by the boat owners,in most threads I've read. The last time I had it out it had to be run really rich to keep it going,and the plug was black. If you got it going pretty good down the straight aways,then let off the fhrottle it would instantly die. It also died in the turns at high speed. I think from all your information,I'll finally get it dialed in,throw the manuals out the window,and keep notes as to how it runs at diffrent settings. Ron

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