525 Intake Sensor
 

what sensor sit in the middle of the intake manifold,,,has an electrical connection on top of it,,,cant find it in the manuals

Most likely IAT, which is Intake Air Temp sensor. However, it could also be your MAP (manifold absolute pressure) sensor. If the sensor is small it is most likely the IAT, if is is a little larger and has a small plastic box on it is it is the MAP.

Go here http://www.mercruiserparts.com/selec...oc_nbr=525+EFI, pic the serial number range that matches your engine. They have exploded views.

Wait....are you talking about Raylar 525's or merc racing 525EFI? ? I noticed you have raylars listed in your signature, totally different engine. The raylar is based of the merc 496 which would be this http://www.mercruiserparts.com/selec...EO%2E+Model%29

no its not a raylar engine,,,,stock 525,,,its not the iat,or the map,,,,i think its a fuel pressure sensor,,,,its sits in the middle of the intake,,,under the plentum,,,maybe its the fuel rail its sitting in,,,,anyway is the fuel pressure sensor near that area

If it's a four pronged, long, oval plug on the port side of a 525 you might be looking at the diagnostic port.

no its not the diagnostic port,,,its in the valley of the intake,,right in the center

Are you talking about number 13 ?

http://www.mercruiserparts.com/Show_...+And+Injectors

If not, a photo may help.
:coolcowboy:

sure your not talking about the PCV?

yes it looks like #13,,,,but wouldn,t it be threaded into the fuel rail,,,this one looks like its threaded into the intake vally???

Yes, it is part number 13 and it is the fuel pressure sensor.

Best Regards,
Ray @ Raylar

figured it out,,,its for the boost ,,,or in my case vacuum gage...lol:drink:http://www.offshoreonly.com/classifi...22&f=38422.jpg maybe iam wrong,,,about the vacuum gage,,,but you can see the red plug in the center of the manfold on this pic,,,what the hell is that for,,,iam lost

anybody????

Fool'in & Tinkering Time?
 

Boy Twin-Spins, you just got that nice new to you boat with those nice twin HP525efi's and you are already "foolin" with it a lot.
Try and remember that saying " If it Ain't Broke, Don't fix it!"
I am sure you've got some "Winter, Northern cold Cabin fever" but it seems like you're start'in to tinker EH!
Hang on spring will be here soon and you can take that puppy out and clear the cobwebs! HA!
Have fun!
If you gotta have more power, send those guys to us and we will send them back Raylar HP675efi's and you can really lay down some smoke on your waters!

Best Regards,
Ray @ Raylar

hey ray does that go for the problem cmi headers too,,,,if it aint broke dont fix it,,,,,or loose an engine,,,lol,,,,anyway taking your advice, ordered two sets of the hurricane lites today,,,boy did i hate doing it,,,what a $hit roll,,,,now ill have some bling to hang up in the garage(old cmi,s):drink:

I was just joking about you fool'in around with the engines themselves, not the header exhaust system.
Sorry to hear you had the dreaded HP525efi cracked Mercury Racing/CMI problem.
That really sucks to have to throw that much money at an 05' top of the line boat you just shelled out the bucks for! I feel for Ya!
Did the pressure test show the old Mercury/CMI's were leaking or did you just decide to loose the risk and replace them?

Best Regards,
Ray @ Raylar

just to loose the risk,,, with a long winter layover,,what works for me is going over everything in my head before ever touching the boat,,that way when i get to the boat its just a matter of doing the labor,,,saves time ,,now that the header problem is going to be solved,,,whats the fix for this gas mixing with the oil lube for the seapump...lol

That's a problem that does not exist in the your model HP525efi racing engines as they now have the fuel pump running off a cam in the sea pump shaft housing and there is no connection between the sea pump and the crankcase oil.

Best Regards,
Ray @ Raylar