Does 1974 OMC 190 have exhaust flapper valve?

[SeanMcl]

Does anyone one know if a 1974 OMC 190 with an 800 outdrive has exhaust flappers? My boat will not get to full WOT rpm, and I am steadily moving though the possible causes. I see no mention of them in the Seloc manual I have, but it seems most boats have them.

And am I right in guessing they would be located where the exhaust elbows connect to the bell housing? I am thinking I just pull the rubber coupler and the lower exhaust elbow off and see what I can see.

Thanks for any help.