Identification help
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Boat Maintenance
Forum Discription: Discuss maintenance of your Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=26328
Printed Date: November-19-2024 at 12:31am
Topic: Identification help
Posted By: srbranum
Subject: Identification help
Date Posted: June-06-2012 at 9:58pm
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GUN Driver and I have been talking a bunch on the phone and I told him I would post some information on what I have and yall tell me what I actually have: Engine: Model number 990311R, Serial#W270197, OMC225 on the Valve Covers, blue in color Rochester Quadrajet carb. Props: 12RH15 Ni-Bral, 1974 12RH16 Ni-Bral, 1967 What engine do I have, and what prop should I be running? ------------- I have to keep her running 'cause I can't afford a new one |
Replies:
Posted By: TRBenj
Date Posted: June-07-2012 at 10:49am
Is this the motor in your '75 Skier? Do you have a reason to believe that its not a 307, as you have listed in your diary? Im not sure which year OMC went from offering the 307 to the 305... but Im guessing it was '75 or '76. Either way, unless youre talking about a much larger engine in a different boat, the 12x15 and 12x16 Federal props are both way too big for a 305/307. A 12x14 Federal would have been the more commonly equipped prop, and even a 12x13 Federal would probably perform pretty well on it. If youre considering upgrading props, either the 12x13 OJ or Acme 1210 (12.5x12) would be the 2 choices I would consider. ------------- |
Posted By: srbranum
Date Posted: June-07-2012 at 1:52pm
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Yes, that's the motor except the passenger side exhaust manifold has been replaced with an after market one. The old one had severe leaks and could not be welded. Of course, the aftermarket manifold does not have "OMC" stamped on it. Gun Driver and I have been talking a ton on the phone and the subject of engines and props came up. I told him what engine I thought I had in my boat which is what the PO told me I had back in 1990 when I bought it and he said it was a 307. I thought with the serial number and model number it would be an easy thing for someone to identify. As for the props, those two props were the ones that came with the boat when I bought it. I would bet that the '74 prop was put on it from the factory when it was built. I just checked the hull ID and it reads: CTC03678M74SKMS So the big question is, if this prop is way too big, why was it apparently installed on the boat at the factory? Also, I just got out the original owners manual and turned to the specs page and it says: Piston Displacement Model 225: 307 Cubic Inches Model 250: 350 Cubic Inches Mine says OMC225 on the valve covers. So do I have a 307? Thanks for responding. I have a straightened shaft, strut, new bushing, reworked prop, repacked the stuffing box, new stuffing box hose to put on and hope to take it to Nashvill next weekend. Gun Driver has provided invaluable help and I am making good prgress. Scott ------------- I have to keep her running 'cause I can't afford a new one |
Posted By: TRBenj
Date Posted: June-07-2012 at 2:02pm
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You can call the factory and see if they can look up the build sheet for your boat. Not sure if it would have any more specific information than "OMC 225" though. If your original owner's manual says its a 307, then I would believe it. OMC also called the 305 a 225 if Im not mistaken, just a year or 2 later. I would expect the 2 motors to perform pretty similarly either way. Its just a bore/stroke difference between the 2, if Im not mistaken. No idea why some boats came with the "wrong" prop installed. My Skier supposedly came with a 12x15 Federal from the factory as well. The holeshot was not very good, and the 12x14 would have been better. Heck, Im currently running a 12x13 Federal and its probably better on my particular boat than either of the others. I really liked the 12x13 OJ that I tried- easily my 2nd favorite prop on this boat. The Acme 1210 that I normally run is the best all around performer. You'd be amazed at what a prop change can do to the way the boat runs. ------------- |
Posted By: storm34
Date Posted: June-07-2012 at 2:03pm
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If you're taking it to Nashville start asking if you can try some different props. I'm sure there will be some folks there who can either let you try one out, or may have them for sale. ------------- |
Posted By: Gary S
Date Posted: June-07-2012 at 2:26pm
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[QUOTE=TRBenj]. No idea why some boats came with the "wrong" prop installed. My Skier supposedly came with a 12x15 Federal from the factory as well. QUOTE] Tim,I'm curious as to how you know a 12x15 came from the factory. When I first got mine I had no prop.I wrote the factory asking what to use,they had no idea. There was nothing on the build sheet for mine. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: TRBenj
Date Posted: June-07-2012 at 2:36pm
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Whether factory or dealer, Im not sure- all I know is that its the "original" prop. The boat originally came from my lake, I have met all the former owners. ------------- |
Posted By: Gary S
Date Posted: June-07-2012 at 2:53pm
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I was just wondering. Back when I got mine I was at a loss and with no internet and of course no CCF to help me out either! I used a couple of old props my Dad had from his Chris Craft days to get me started,and had always felt they were lacking. Thanks to Reid who got me set up with a Federal 12x14 as a spare and an OJ 12x13 for everyday. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: srbranum
Date Posted: June-07-2012 at 3:34pm
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Emailed the PO and this is his response, talking about my boat I bought from him in 1990: "I think your boat came with a 12X14 or a 12X15(the first number is the diameter in inches and the second number is how many inches the prop would travel forward through the water in one revolution if you think of it as a screw. Nautiques came with a 13X13. The "12" is fixed. The proper way to determine the second number(pitch) is to select the number that allows the engine to run 4800RPM at WOT. The 1967 prop came off my ex-brother-in-law's 1969 Correct Craft. Note: Your Chevy engine runs stronger than the Ford 302 that was standard so you may have to run a number higher on the pitch to keep from over revving the engine at WOT" >>>>>>>>>>>>>> Must be nice to know what your talking about, I would not know  ------------- I have to keep her running 'cause I can't afford a new one |
Posted By: TRBenj
Date Posted: June-07-2012 at 4:17pm
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Some of that info is correct (explanation of diameter and pitch)... some of it is not. You do not want your engine to turn 4800 rpm at WOT unless that is where it makes peak hp. What is called out in your manual as the "max operating RPM"? More likely, it will perform better and run faster if you prop it to turn 4400-4600. Having a more powerful engine does not mean you need a prop with more pitch. Like I said above, its a game of matching WOT RPM's to the horsepower curve. Since the 302, 305 and 307 were all very close in displacement, they were all propped the same, as far as I can tell. Chevies in general tend to breathe a little better than the Fords, so they tend to make a *little* more hp, which peaks at a *slightly* higher RPM. So, in effect, you spin the same size prop for both powertrains- the higher hp one simply turns the same prop a little faster. A motor with larger displacement (350, 351w, etc), on the other hand, would require a prop with more pitch to keep the revs in check. In regards to diameter, thats not really "fixed" as was suggested. What you need to watch carefully is the prop to hull clearance. 10% of the prop diameter is the general rule of thumb, but you can encroach on that a little bit. Having ~1" of clearance between the hull and tip of the blade on these hulls is about as close as you want to go. The 16' boats like the Mustang/Skier/Tique came with 12" diameter props from the factory, while the larger boats generally came with 13", or sometimes 14". A prop with a slightly different design (like an Acme, which will have aft-raked blades) will allow you to turn a slightly larger diameter prop (12.5" on the 16' boats is just fine) without encroaching on that minimum clearance. ------------- |
Posted By: srbranum
Date Posted: June-07-2012 at 9:56pm
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TRBenj, The manual states: "Full Throttle Operating Range----4000 to 4400 RPM" ------------- I have to keep her running 'cause I can't afford a new one |
Posted By: gun-driver
Date Posted: June-07-2012 at 11:58pm
I'm going to bring the 13x13 Federal that came on my '85 for him to try. But that maybe to wide, I could bring the 540 from the '85 if you guys think it would work on his boat. |
storm34 wrote:Posted By: TRBenj
Date Posted: June-08-2012 at 11:27am
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Both the 540 and 13x13 Fed are too large in diameter and inappropriate for this application. Based on the above statement in the manual, I'll agree with my original guess that propping the engine to run in the 4400-4600 will net the best all around performance. If you ask Reid really nicely, he might be able to bring a 12x13 OJ and a 1210 Acme for you to try. ------------- |
Posted By: gun-driver
Date Posted: June-08-2012 at 11:35am
| I thought they may be to wide. |