Measuring Exhaust Catalyst (EC) Manifold Risers
How do you know what size exhaust riser kit to order for your catalyzed Mercruiser engine?
A common question we get is "how do I know what size risers I have installed in my catalyzed (EC) engine?" Your serial number may indicate the engine came with 2", 4", etc. risers but along the way it may have been changed it out to another size to fit your boats needs.
The fastest and easiest way to figure this out is to look at your intermediate elbow. The intermediate elbow is also referred to as the "down tube". This connects to your Y-pipe aka exhaust pipe. See parts diagram here:
On the side of your intermediate elbow there will be a number and under that 2", 4", 6", etc., as shown below.
In this case it's a 2" elbow which means you'd choose a 2" riser in the Exhaust Manifold & Elbow section of the parts diagrams look-up (see below).
See the Notes colum where it shows you this kit includes both elbows. It also includes anything indented under the main part number.
We hope this helps you figure out what you have! Please use the Contact Us tab for quick answers to your questions!