Can some one explain the difference between the two?

you are asking the difference between a NON CAT engine 496 to a (ec) emission control 496 ? correct and are we talking about Mercruiser here ? there is more than just Merc who had 496 EC engines.

Mercruiser to hopefully guess correctly.

There is a big difference, the PCM is totally different, - PCM 09 Visteon compared to PCM 555 Motorola. The EC engine with PCM 09 computer - you have 4 - O2 sensors installed in the exhaust system - a pair before the CAT and a pair after the CAT, the exhaust manifolds and riser are totally different because they have to hold 3 per side total of 6 cat sub strakes cores mounted vertical internally. DUMB idea plus a lot more expense as everything currently is one CAT per side facing horizontally.

The wiring harness is different as well. You can not run a EC engine out of gas - it can blow a hole straight thru the CAT sub strake(s). You can not let any cooling issues linger - whether very minor to extreme - you can not continually run your engine while misfiring and so on. These problems will degrade or ruin the CAtalyst system. The 496 sub strakes cost 1200 bucks per one then times 6. Not cheap if you were to damage all six and again I am talking about any form of damage from very mild to extreme. .

The PCM fault codes jumped up another 150 added on top of the already 236. Maintenance and on time with it for an EC engine is now way more important than it was before - An EC marine engine will or has knock out at 90 % of the do it yourselfer for repairs and especially for diagnostics troubleshooting - so on my end that is welcomed - just saying no offense.

All EC's 496 if I recall correctly were DTS so no IAC or IAC mufflers so the throttle body is different plus no mechanical shifting and different components. There is more but here is the jist of it. I would pass on any of the 496 EC engines just my IMO.

Thank you for the response. Next question would be how do i tell which one i have, engine serial number?

Simple the exhaust manifolds & risers and cover plates for the O2 sensors. Next is of course engine serial # and year model (both) needed.

So you are saying you have a Mercruiser - so what year ? that will tell me a lot - if you have a stock 2002 Baja like your deal says up here then YOU HAVE a NON EC 496. NO CATALYST ENGINE. If you repowered or someone else did then pics are worth a 1000 words here.

California had all 496 EC engines in model year 2008 CARB mandated / EPA - the end of 2007 some in market as well in CA but the rest of the USA started in CATALYST engines in 2010 then very soon the 496 went away. Replaced by the EC 8.2 and still is currently by Mercruiser. .

Thx again for response, yes all stock 2002 model, so as you stated it should be noon ec. Thx

Man if only you posted that info to begin with, I would not have written the novel.

Much simplre for both of us - tell it like it is and really what info you are looking for. I thought at first you want to convert hence the novel.

"I have a 2002 Mercruiser stock 496 is this an EC engine or not" - that simple. Good luck

Sorry my man, you where for sure Johnny on the spot. Just think of the good you did for all us guys needing just some basic knowhow of our boats motors. Again thank you for your time.

Johnny on the spot because that is the majority of engines I have to crawl all over these days. OK more info for the inquiring minds - the end user is the main source of engine related problems and failures of EC emission controlled Catalyst engines.

A side note your welcome

How can I tell if my 2005 Smartcraft 496 Mag is DTS ready or not ?
It currently does not have the DTS shifter/throttle.

Thanks

To start with you will need the shift actuator and that bracket, then hardware, then harnesses and shifter (control box helm) then the correct key switch. DTS has a feature called auto start. IMO its nice how it shifts but really it has a slight delay when shifted - I do not like that part of it. Also I have seen the actuator fail and I have seen a few bad right on brand new boats.

the actuator is 1300 bucks plus you will need more to than that to complete the install and that's not counting labor either.

Link to see the actuator and other parts of just that end of it.

prices are listed as you scroll down.

http://www.marineengine.com/parts/me...le-shift-axius