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hp after rebuild merc 502

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Old 06-29-2013 | 08:27 AM
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i use the boot for cruising, but also a lot of flat out!!

so a bigger carb is necessary. i will look for one but are not that easy to find in the netherlands.

the motor is in a 23,5 ft boot (freedom, hull by Baha)
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Old 07-12-2013 | 12:19 PM
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i an now getting 68mph @ 5200 rpm with a mirage plus 23. i have tried an 26 bravo, ran 4600b rpm same speed. and a revolution 25 @ 4900 rpm also same speed.

i should think there must be more in it.. what could it be.. before rebuild i dit 67mph so not much profit.

Other question, i still run the original spark plugs, ngkbr6 , with this high compression what is your advise to use as spark?

the other problem we have is that the oil temprature is getting high over 250F watertemprature is perfect @150F what can cause this?

Last edited by pelikaan; 07-12-2013 at 12:37 PM.
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Old 07-16-2013 | 09:37 AM
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What oil are you running and you may need bigger oil cooler.
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Old 07-18-2013 | 09:09 AM
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i am using kroon atlantic 25w 40..

i am thinking about getting a bigger oil cooler.
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Old 07-18-2013 | 08:23 PM
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Originally Posted by vintage chromoly
You should have no problem getting 550hp from a fresh 502. (Especially with that compressiThat carb is way too small for that engine. You need an 850.
thinking the same thing hence the hi temperature.
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Old 07-19-2013 | 05:41 AM
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I agree with trying an 850 Holley carb. Oil temp is high.
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Old 07-31-2013 | 12:16 PM
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i am looking for an bigger carb but wil start getting some bigger jets for the edelbrock 750. this must give an difference.

wat max rpm would be good for this setup? the cam is for 1800 to 5800. thinking 5800 is a bit to much for the original crankshaft.
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