Engine Rebuilt Nightmare
09-08-2011, 05:19 PM
#22
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Just order an Air/Fuel Ratio meter.
I will post my readings when I get it and hopefully I can get some good feedback.
Thanks again for all the replies!
I will post my readings when I get it and hopefully I can get some good feedback.
Thanks again for all the replies!
09-08-2011, 08:50 PM
#23
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Side note, I agree 100% on the props. I have had different styles of bajas and everyone says B1. Some worked ok, but the 3 blade mirage or quicksilver out performs on top end for me every time. Definatly has more bow lift, just not as good out of the hole.
09-08-2011, 09:51 PM
#24
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09-09-2011, 12:19 AM
#26
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No, you will need to weld an O2 bung in the collector (if it's a header) or riser (if it's manifolds). The egt bungs is probably only 1/8" or 1/4" NPT where as the O2 sensor is 18mm.
Eddie
Eddie
09-09-2011, 08:15 AM
#27
X2, I just welded O2 fittings into two of my tailpipes.
One thing to remember is that if you do have the o2 sensor installed, it has to be powered up, or it will dramatically shorten it's life.
The sensors don't react well to the marine environment, so put it in only when you intend to take A/F readings, and take it out and install the plug the rest of the time.
One thing to remember is that if you do have the o2 sensor installed, it has to be powered up, or it will dramatically shorten it's life.
The sensors don't react well to the marine environment, so put it in only when you intend to take A/F readings, and take it out and install the plug the rest of the time.
09-09-2011, 09:25 AM
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X2, I just welded O2 fittings into two of my tailpipes.
One thing to remember is that if you do have the o2 sensor installed, it has to be powered up, or it will dramatically shorten it's life.
The sensors don't react well to the marine environment, so put it in only when you intend to take A/F readings, and take it out and install the plug the rest of the time.
One thing to remember is that if you do have the o2 sensor installed, it has to be powered up, or it will dramatically shorten it's life.
The sensors don't react well to the marine environment, so put it in only when you intend to take A/F readings, and take it out and install the plug the rest of the time.
Thank you guys!!
Last edited by TW720HVY; 09-09-2011 at 09:27 AM.
09-09-2011, 09:39 AM
#29
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Sound Right??
I was going to get into the entire chain of events from the engine builder that had our engine the first week of Feb that did not get it to me until the week of July 5th! To the two so-called friends in the marine business who I was willing to pay to help me install everything all the way down to having to pull the engine three times!!!! For advice the coupler was bad to it was never aligned from the factory correctly!!! Oh and the most important thing, the radio stopped working and our soft band new cooler has a hole in it!
Well, finally the boat was put together and in the water for the Shootout last weekend. Good news for the most part.
The boat is a Baja by Fountain 26OL with the stringer hull, you remember the one Reggie got 69MPH out of for the Powerboat article. The engine is a 496 that was rebuilt from the crank out with Dart Heads. The best dyno was 560HP/544TQ @ 5400RPM. I was hoping for a little more, 575HP would have been cool but I guess I can strap on my Briggs & Stratton for the extra 15HP.
I also put on an IMCO neutral extension box with IMCO 2" shorty. Measured the distance from the keel to the prop shaft centerline and it is 4 7/8"
The first day on the water with her I was spinning a Bravo1 26P Merc labbed prop. It was only giving me 4900RPM and a top speed of 66MPH. (Before all the up grades and tons of $$$$ I was getting 61MPH) This past weekend I put the old 23P prop back on and was getting 5400RPM and still only 66MPH. So the fun of getting the right prop begins. Any suggestions would be great and I haven't had the chance to call any of the professional prop guys yet. Surely I can get more out of this boat than just 5MPH.
Another issue I am having is the idle. It idles like crAAp and I am thinking it has something to do with the fuel pressure. The original dyno had a fuel pressure of 44.5PSI @ 2800 and 41PSI @ 5400. with an average of 42.5 PSI @ 4100 I was told this will damage the engine. So I installed an adjustable pressure regulator and at the 11th hours I threw my hands up and told the shop that was aligning it to install it and set it at 49PSI. They set it at 52PSI so they told me. What are some of the thoughts about the PSI and where should it be base lined? I know this all depends on the engine and spark plugs. Can someone share or point me in the direction of a good reference for spark plug inspection? So I know what to look for while I fine tune it some more.
Sorry for the long winded post and I hope my ranting makes sense. And if you are reading this and love your boat but you are thinking about doing this one day I would suggest you don't if you do not want to start hating the very sight of it.
Well, finally the boat was put together and in the water for the Shootout last weekend. Good news for the most part.
The boat is a Baja by Fountain 26OL with the stringer hull, you remember the one Reggie got 69MPH out of for the Powerboat article. The engine is a 496 that was rebuilt from the crank out with Dart Heads. The best dyno was 560HP/544TQ @ 5400RPM. I was hoping for a little more, 575HP would have been cool but I guess I can strap on my Briggs & Stratton for the extra 15HP.
I also put on an IMCO neutral extension box with IMCO 2" shorty. Measured the distance from the keel to the prop shaft centerline and it is 4 7/8"
The first day on the water with her I was spinning a Bravo1 26P Merc labbed prop. It was only giving me 4900RPM and a top speed of 66MPH. (Before all the up grades and tons of $$$$ I was getting 61MPH) This past weekend I put the old 23P prop back on and was getting 5400RPM and still only 66MPH. So the fun of getting the right prop begins. Any suggestions would be great and I haven't had the chance to call any of the professional prop guys yet. Surely I can get more out of this boat than just 5MPH.
Another issue I am having is the idle. It idles like crAAp and I am thinking it has something to do with the fuel pressure. The original dyno had a fuel pressure of 44.5PSI @ 2800 and 41PSI @ 5400. with an average of 42.5 PSI @ 4100 I was told this will damage the engine. So I installed an adjustable pressure regulator and at the 11th hours I threw my hands up and told the shop that was aligning it to install it and set it at 49PSI. They set it at 52PSI so they told me. What are some of the thoughts about the PSI and where should it be base lined? I know this all depends on the engine and spark plugs. Can someone share or point me in the direction of a good reference for spark plug inspection? So I know what to look for while I fine tune it some more.
Sorry for the long winded post and I hope my ranting makes sense. And if you are reading this and love your boat but you are thinking about doing this one day I would suggest you don't if you do not want to start hating the very sight of it.
If you go by 425 prop shaft HP of 496 HO @ 61mph, think of the following.
If you had 560 dyno hp, and account for 10% hp loss of 56 HP at the prop due to parasitic drive loss, you would be looking at 504 prop shaft hp.
Now take the 504 and subtract 425 prop shaft HP and you get 79 hp gain over the stock motor.
Now if you rate 15 HP approx for each mph and multiply by the 5 mph gain you get 75hp. Sounds pretty close?
This extra HP you have and the 66mph may be realistic.
Just my thoughts. THX
09-09-2011, 10:29 AM
#30
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Some things to consider?
If you go by 425 prop shaft HP of 496 HO @ 61mph, think of the following.
If you had 560 dyno hp, and account for 10% hp loss of 56 HP at the prop due to parasitic drive loss, you would be looking at 504 prop shaft hp.
Now take the 504 and subtract 425 prop shaft HP and you get 79 hp gain over the stock motor.
Now if you rate 15 HP approx for each mph and multiply by the 5 mph gain you get 75hp. Sounds pretty close?
This extra HP you have and the 66mph may be realistic.
Just my thoughts. THX
If you go by 425 prop shaft HP of 496 HO @ 61mph, think of the following.
If you had 560 dyno hp, and account for 10% hp loss of 56 HP at the prop due to parasitic drive loss, you would be looking at 504 prop shaft hp.
Now take the 504 and subtract 425 prop shaft HP and you get 79 hp gain over the stock motor.
Now if you rate 15 HP approx for each mph and multiply by the 5 mph gain you get 75hp. Sounds pretty close?
This extra HP you have and the 66mph may be realistic.
Just my thoughts. THX
