I’m hoping it’s just clogged fuel filters from bad gas last year since both motors have very similar performance loss at the same time. That would explain leaner AF readings not being able to properly flow fuel but I’m still at a loss with oily suit on transom unless it’s coming from drives, steering and/or tabs.

SecondWind,

As someone who's suffered the renowned 496 "transom soot", your "oily soot" tells me a very RICH exhaust. In your case, it may be incomplete combustion. Fouled plugs from your winterizing program....? You also may be burning some oil. Just speculating. Really just replying to follow.

Thanks. Brad.

Yes I’m not sure what’s going on. I’m going to start by replacing fuel filters since that’s easy and see if that helps improve performance and normalizes AF readings.

SecondWind,

Pulled the spark plugs? What did they look like?

Thanks. Brad.

So the fuel tank sat almost empty all winter?

Ryan,

Curious to see where this leads. I've heard compelling arguments on all sides of this question. Leave it full. Leave it empty. Half full....

Thanks. Brad.

Yes it did.

I’m not sure I could do that if my life depended on it. Absolutely no room to work in the engine compartment and my back is stiff as a board. I’m going to take it in and have a professional take a look.

SecondWind,

Ya know.... Sometimes I wish I had twins....

Thanks. Brad.

Interesting. I could see an argument for leaving it COMPLETELY empty, but i always thought it was pretty black and white that a small amount of fuel gels up quicker than a large amount.