502 Mag EFI question

[Robby]

I'm looking at a 1993 253 with a 502 mag efi. Wondering what the pros and cons are for this motor and when and why did they switch to MPI? And does K&N make a flame arrestor for this set up?

Thanx

 

[Big Red]

The 502 efi is a good engine. Your only concern is if the previous owner mantained the engine properly. K&N makes anything for every application.

 

[happy]

yes k&n makes a filter for that engine, you can expect some, if any midrange, as with any other thing in society that works, the goverment decided that the "dirty engines" needed to be cleaned up, so efi was the answer,, and remember in the states, at least, the marine engines are at least 10 years behind the auto industry.

now the techonolgy is catching up, so catalytic converters are being installed in some areas of the country.. Californaia namely, but the trend is moving .. as far as my shop goes 100% of the used boats that come from there have damaged engines.. i guess it cost too much to fix em out there, so thet sell them elsewhere

502 is a strong moter and has years behind its rep.. its just like the now called old 350 its rock solid.. and time tested,

 

[Old Navy]

Do a compression or leakdown test on it. They used some metric rings on those and some had cylinder pressure problems, not all. Otherwise a good engine. It probably needs a Procharger.

 

[happy]

the whipple system is better, too much bulk with the pro charger, and its oragomay looking

 

[onthehammer]

Please tell me you are not considering putting this in your senator??? If you are I'll say a prayer for you.

502 was first EFI in 1993 if I remember correctly. So that would mean that the 93-97 models were v-belt systems and 98-01? were serpentine. Great engines for stock and a little more. Would need serious workover for any kind of blower set up to be reliable. usually these engines would need to be decked and have the heads trued on them. If I remember right I think it is the number 5 cylinder that likes to blow out the headgaskets and detonate when trying to make any serious power on a used one of these tried and true beasts.

 

[Robby]

If I had a spare and I was keeping my boat I'd give it a try!!!!!!! Kidding aside, I have a deposit on my boat so the sale is pending. We decided to go a little bigger and a 25'r looks like it is going to suit our needs. I heard the price of fuel is going to drop the summer.......... yea right! Small block to 502 will change things a little, my $50 fuel weekends are over. Looking foward to a better ride though.