What is the difference between a 502 mag, and a 502 ho.?



Is there such a thing as a 502 mag ho?



How do you tell the difference? if they put a different manifold on it. How do you tell which one you have. There is no label on the top of the engine.

I bought a boat fallof 2010 and after getting it home, and looking at the description it said 502 mag ho. The man I bought it from was a complete idiot. The previous owner made all the changes to the engine. Just curious. After reading stuff on this web site i am confused , because the guy knew nothing about the boat except where to put the gas in it. and I wonder now how accurate the description is. The boat does between 80- 85 mpg, The original owner said it would do 80 all day, and he got it up to 85 on gps , Also there is a m1 procharger on it. It is a 1997 24ft outlaw sst crated 2009
502 ??? . And the rest of the engine has parts from the other 502 . I won't really know the true horse power until i have it dynoed . The idiot said 620 horse power, but now i don't believe anything on his sales paper. I have had the boat up to 78 mph myself so i do believe it will do 80, becasue i still had room for alittle more speed. the boat runs good, except for a new gimble bearing i replaces and a serpintine belt, and i have to add hydraulic steering in the spring and a msd box with a rev limiter

Any insight would be appreciated?

502 MAG HO just came out in the last year or two. Current Merc 502 offerings: 502 MAG- 380 HP, 502 MAG HO - 430 HP. These replaced the 496s used form about 2001 - 2010.

Previous generations of 502 MAG MPI were all 415 HP (1994 - 2001ish). Prior to that I believe the carb versions were 390 HP????

I'm sure someone could provide more details.

You could have anything in there.

Yup.

Before '94 hp ratings were all over the place. But if you go by the way they rated them since '94 the 502 MAG was 410 hp in '90 and 405 hp in '92 ect. I can dig '91 and '93 up if you like? After that, they went one way with it, SAE J1349 C.hp even though it says prop hp. Only motors that did not do this, was the high performance. They go by SAE J1349 by their name ie. HP500, 500 C.hp, HP575, 575 C.hp ect. It's quite confusing. Finally managed to get the low down on this from Dirk Meyer of Merc about two-three years ago. This is simply because all are sold as bobtails. Forget the prop rating stuff, it's just promotional mumbo-jumbo. I know Dustin Whipple have done quite a bit of testing on the stock merc and merc racing motors. He usually hits within +/-2% of claimed hp on both black and blue motors when testing SAE J1349 C.hp. Sorry if it got off on a bit of a tangent, just some info.

Here is an example.

Thanks for the insight, I do remember the original owner said he converted the 502 crated motor from fuel injected back to carburated because it was easier when he installed the procharger and if my calculation is correct and by the info from the 1st owner the crated 502 is a 2008 or 2009 .
The 1st owner said the total horsepower with all the modifications he made: m1 procharger, better manifold, and not sure what else, is at least 620hp, this was on the sales sheet. i bought it on halloween in 2010. i hope i didn't pay to much,. I guess i won't know what i have for sure until i get dynoed, but it does 80 mph , so i must some hp pushing me through the water.

I swapped my boat for his and paid the difference. I sold my 19ft 1989 baja es with a 3.0 engine, in mint condition for $2000 over book sold it to him for $6000. I bought this 1997 outlaw sst w/ trailer in good condition for $24,000. When i booked it i figured the value to be around $28,000, with the 2009 crated block, and procharger. i booked on kelly blue book with hp 471-500 w the 8.1 liter option for engines. Because he said it had 620 hp, and he didn't know the liter of the engine. I booked it with that horse power and the other options. it booked on there for $28,000 with out the price of the procharger, and better manifold, and the charger i looked up go for $5000 or so, it is only a few years old. Plus the boat has two fuel pumps on it. And the 1st owner re did the stringers in the rear of the boat. since i was selling mine for well over book and he never looked it up i didn't want to push the price of the 24ft, After all said and down with my boat for trade and getting the 1997, i ended up paying $18,000. So did i screw my self for jumping on it to quickly and trying to beat the snow flying or what, i am happy with the boat,, only thing i need to do is put full hydraulic steering on in the spring to correct line walking at 73 mph and above, and , new gimble beerings, and i need to put a msd box on it, and a rev limiter, because when the procharger was put on the rev limiter was never put back on and listen to you guys i guess the best way to go is a msd box for my boat

i appreciate any replies and advice,

thanks

If you are running 80 as an everyday number, you are pushing about 525-550 hp depending on setup.

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So with all the information i have put on the previouse thread, Do you think i screwed myself and got ripped off on the price. Even though i sold mine for 2000$ over high book value?

in your opinion?

be nice, don't slam me to hard or sink me in the water

i am very happy with the boat and the performance of it, it was more then i asked for in the speed category, i was only looking for a 60mph boat not this monster

My mechanic was driving when we had it up to 78 and he said we had more trim to bring up, I am not sure if he was talking about the trim tabs , or he was moving the out drive trim. he backed off at 78 mph, but he said the boat would definitly do 80 for sure. We were line walking aliitle. Trying to think back I think it was the trim tabs because I didn't feel the boat get lighter in the water, like when you bring up the outdrive. That feling when the front feels lighter. I talked to the original owner and he said the boat had 620 hp or maybe even alittle more becasue of the extras on the engine. I don't know now what it has , after you saying it has only
525- 550hp, I am sure you are probably accurate,
He did say he had it gps at 85 mph one time on the water, So I guess with his calculation the boat has done 85mph. 80 mpg is plenty fast enough for me. The 1st owner said he used to put octance boost in the engine and he always ran at least 91 octance. I run 94 or the highest at the pump, and always 91 or higher
I guess I really won't know until I get it dynoed, by a race shop. I know that 78 mph is really fast. and we were doing it in a 2 foot chop into the wind.

I have a 4 blade custome spinellie prop, good or bad? don't know the ptich.