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Boat Repair/7.4 L I/O Serial Numbers

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Expert: Jeff Grigg - 1/23/2008


Question
QUESTION: Trying to order a new engine manual from Mercruiser, but cannot read the serial number on the flame arrestor any longer.  Do you know where this may be stamped on the engine somewhere? I can read the lower unit serial number.  Do they correlate? I tried to order one already by giving them the info. I knew and they sent me one for the fuel injected model but I am carburated.

ANSWER: Some of the motors have a serial plate on the back of the motor, but most newer models don't. If your engine is original to the boat give me the serial number off of the transom and I can look up the manual by year and post back the part number of the manual.

---------- FOLLOW-UP ----------

QUESTION: Well, the lower unit number reads: OF652024 (Bravo I)  The motor has been replaced.  The original was a Mercruiser Gen 5 7.4L 300HP.  The new motor I am told is a Gen 6 Vortec 7.4L 330HP Carbed.  Thanks for your help.

Answer
Shawn, I believe this is the correct manual. 90-8232242
I would call your local dealer and give him the same information you gave me. There is also an engine code on the front of the motor around the water inlet on the starboard side, that may help also.
Jeff

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Jeff Grigg

Expertise

Can help with most any question related to outboards, high performance, hull repair, rigging, if it floats and uses a motor. From a 9.9 on a aluminum boat to DFI two strokes. Outboard motors are my specialty. I can help with some I/O questions as well. Ratings are the only way we know if we are helping. If you are pleased with the help, please rate us. 20% don't bother reading my answers! If you are not going to read the follow up then why ask? Keep in mind we do this at no charge and are not paid. We do it to help you!

Experience

32 years in the marine business. Own a service facility, in coastal South Carolina certified Master Tech by Johnson/Evinrude, certified Mercury/Force, Tohatsu/Nissan. Former technical director for DMI Pistons. 30 year racing career including 3 APBA Formula V National Championships

Organizations
AMTECH, APBA

Publications Written For
Boat & Motor Dealer, Car Classics, Custom Vans (tech articles), Miami News, powerboat racing column

Awards and Honors
Certified Master Technician Johnson/Evinrude

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