Author
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Topic: Dauntless 18, 135 OptiMax
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doscaballo |
posted 03-28-2007 09:36 AM ET (US)
Hi. I just took out the 1998 Dauntless 18 this last weekend after getting it back from the shop. This was the first time I have had it out on the water since purchasing it.One thing I noticed is that the engine speed seemed really high for the boat speed I was going. I thought the tachometer might be in need of calibration. It easily went over 6,000 if I gave it full throttle. I only kept it there for a second. [The propeller has] four blades, stainless steel, but I cannot see the manufacturer's name. I checked the prop that night and by measuring, it looks like it's 13-inch diameter. A fragment of the part number has "17p" in it, so I assume it's a 17-inch pitch. I looked at WHALER.COM performance data, and they use a 15.5-inch 17-inch pitch propeller. This is making me think I am way under-propped motor for this boat. Does my boat seem under propped? If you have a similar setup, tell me what propeller you are using. Thanks in advance, Mike
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nydealer
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posted 03-28-2007 01:06 PM ET (US)
I think Whaler may have shipped it out with a 17P but two of the 18 Dauntless I looked at from 1099 and 2001 had 15-1/4 x 19 P Mirage three-blade. Your RPM range is 5000-5500. You don't want to get above that. |
Lars Simonsen
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posted 03-28-2007 08:36 PM ET (US)
I have a 1998 Dauntless 18 with a 135 Optimax as well. I had a stock 17-inch pitch aluminum propeller originally, and it was definitely under-propped. I now have a 19-inch-pitch 3-blade Stilleto stainless steel. I also raised the motor up to the middle hole. I'm very pleased with the set up. Once I raised the motor, however, I found that I had to come off plane more slowly, as my stern would sink more, and if I came off plane quickly, I could get water into the motor well. Since then, I've also put trim tabs on. Now, when I'm coming off plane, I lower the tabs and trim the motor down. This keeps the stern up, and also puts you in the position to jump back onto plane when you take off again. |
doscaballo
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posted 03-29-2007 02:49 PM ET (US)
Ny and Lars,Thanks for the reply. I think I definitely need to investigate this more. Lars, you said you currently have a 19 pitch prop. Do you happen to know the diameter of it? Thanks again, Mike |
Lars Simonsen
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posted 03-29-2007 09:05 PM ET (US)
I don't but I'll see if I can find out. Lars |
Tom W Clark
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posted 03-30-2007 01:14 AM ET (US)
The three blade Stiletto to fit a 135 OptiMax is the Advantage II. The diameter of the Stiletto Advantage II is 14-1/4". |
doscaballo
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posted 03-30-2007 08:21 AM ET (US)
Thanks everyone. I called the local Boston Whaler boat dealer and he claims that similar setups have always come in with a 15.5 x 17-inch- pitch Mirage. I ordered a Solas aluminum with the same specs last night. I will have to hold off on the stainless for a while. In the meantime I hope to get my WOT RPM into specification. I will try and post some results.Thanks again for all the help, Mike |
jimh
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posted 03-31-2007 03:23 PM ET (US)
I think most of the time the "Mirage" propeller is mentioned here the actual,propeller being discussed is the Mercury MIRAGEplus three-blade propeller.The marked pitch on a Mercury MIRAGEplus propeller is often somewhat understated, or, in other words, a MIRAGEplus marked with a 17-inch pitch often performs like other propellers marked with a higher pitch, say 19-inch. I have tested a MIRAGEplus propeller in several pitches, and, when comparing them to other propellers, found that they consistently performed as though their pitch were about 2-inches greater than that marked on the propeller. |
Lars Simonsen
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posted 03-31-2007 04:47 PM ET (US)
I looked today, and my propeller is a Stiletto Advantage II 14.25 x 19P, as Tom Clark said. |
lakeman
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posted 04-01-2007 07:01 PM ET (US)
I'm running a Mirage Stainless steel 3 blade 17 inch and I get about 53-55K RPMs depending on trim water conditions and if the Bimmi Top is up. Just about perfect for the 135 opti on my 2000 18 Dauntless. |
sosmerc
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posted 04-02-2007 12:51 AM ET (US)
The Optimax 135 should be sounding an alarm and going into "Guardian Mode" if you are really turning 6000 RPM. You should be up against the rev limiter. I think maybe your tach is incorrect...possibly due to the calibration dial being in the wrong setting. The calibration screw should be set for 2 stroke/6 pulse. |
Lars Simonsen
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posted 04-02-2007 09:29 PM ET (US)
I had a 17" pitch aluminum prop on my 18' Dauntless with 135 hp optimax when I first got the boat. It would also easily rev to 6000 rpm, and it was clear that it would keep on revving if I had pushed it. So if the 1998 optimax has an alarm/rev limiter(which I assume it does), it didn't work on mine either (not at 6000 rpm, anyway). With my new 19p prop, I can reach 5500 rpm redline, but it takes full throttle, and the motor trimmed up as far as it can go without ventilating. |
sosmerc
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posted 04-03-2007 10:13 PM ET (US)
Limiter on a 1998 135 Optimax is supposed to kick in at 5800 RPM. If you stay "on the limiter" long enough, you should get a steady, beeping horn.....and eventually rpm's will be reduced to 3000. At least this is what is supposed to happen. |