what is the difference between 500 efi and 525 efi
 

except one being a newer model what are the differences between 500 efi and 525 efi what is an average running time untill the rebuilt of a 500 efi and is there any disadvanteges for that type of engine .
thanks

25 efi's.

differences- 525 has alum. heads and FWC.

Some good info: http://www.offshoreonly.com/forums/s...ghlight=500efi I think the bottom end is also different.

65 more hp in 525 efi

Closed cooled, Edelbrock aluminum heads, long tube vs. E-top headers, etc..

Both motors should get a top-end job around 200-250 hours.

The short answer is that there is quite a big difference. Other than both being 502's, they don't share much beyond the basic block and intake manifold

I knew something like this was going to be in the first replies and I STILL laughed.

:cool-smiley-027:dagnabit, that was what i was going to say

Yea, that was pretty funny.

.....What can I say??

The 525 has all forged internals and a full roller valve train. It's a very stout package and only pumping 8.25:1 compression ratio, it's hardly working. Plus it run's on Regular 87 octane gas (Mercury Recommended)

I think the header issue has only come into play in saltwater useage. I know of several freshwater 525's that are still operating trouble free.

I have 300 hrs on my 02 500 EFI s in my Top gun, trouble free so far 82mph on my GPS

Ask the racer's that run the 525 in OSS SVL, they will tell you it is a great motor package. some of the team are running the same motor for the 4th season, with just oil changes and plugs.

When you say rebuild top end at these hrs is that for the guys who are running WOT and pushing all the time? I know so many that have exceeded these hrs and have not touched a thing and they keep on ticking....

Both are great motors but personally I like the 500 because you don't have all the problems with sensors sending it into gaurdian mode. It is VERY easy and only requires a few minor changes to get a lot more power out of the 500 then what the 525 makes.

Heads, Cam and ECU reprogram and you are at 600 HP and it looks stock and idles like a stock motor.

I have seen a few motors have top end problems at or around 200 hours but very few. I know of several 500's with many more hours that have been trouble free. A mercury tech at the miami show told me that most if taken care of will easiely do 400 to 500 hours.

The comp ratio is 8.75 on the 525EFI and 500EFI. The 500EFI aslo has all forged internals and a full roller valve train and runs on 87 octane.

The main differences are the cam, ECM, aluminum heads and closed cooling on the 525EFI.

300 hrs on my 500 efi's and just had the top ends done on both, He said that they were both in great shape but better safe than sorry

Can you make that with the carb motors?

It's just a recommendation from Mercury. Some are going to look better than others at these intervals.