I have a 2009, 35hp LT with only 44hrs. Yes, true hrs. Noticed it was using oil, spark plugs had carbon on them, and had oil on the air filter. Took it to shop and they ran a leak down test. Had 60-65% leak on both sides. I treat my motor very well. Change oil, oil filter, gas filter, new spark plugs (autolite) every year. Motor is garage kept. Valves were fine, set right, but both head gaskets blown. What could cause this with only 44hrs. No mods, stock everything. As I look back, could have started having loss of power at 30hr range. Thought it was bad prop and dinged up hull. Anyone have this kind of problem with so low hrs?

xx

Hopefully didn't get a lemon especially since out of warranty. Weird thing was still ran 20-21mph with just myself, and 17mph with 3 guys and medium hunting load. Thought with that much leakage I would have seen much more loss in speed and power.

If heads are off anyways do a valve job and resurface them at minimum. Imo

Head gaskets can go for any multitude of reasons. I'm replacing mine. I noticed some small leaks aswell. Def gotta check for flatness on the heads. I did notice a small loss of power, samething you described. I've been blaming it on the prop. After i get the engine back together I'll test it. See what kinda compression numbers, and speeds I'm getting.
Good luck with yours

Will look at flatness of heads. Don't want it to become a chronic problem. Thanks for insight, will let you know what I find and how it does after fixing.

When you say valve job, please explain. Not a mechanic, but I did stay at a holiday inn express.

Briggs valves from factory usally dont seal well . If heads are off anyway it an easy job for most machine shops. The aluminum the heads are made of tends to change shape abit after alot hot cold cycles, a resurface insures heads are flat

It's not good for engines to be used that sparingly. Considering the history of these engines, and not calling your mechanic faulty, but it could be dried up valve stem seals and leaky valves. Leaking valves are 98.73% of the problem source when a leak down is performed on these engines. However, even if it were the valves and valve seals causing the issue, you will have to pull the heads and will get new head gaskets anyway. But I wouldn't just pull the heads and install new head gaskets without working the valves and changing the valve stem seals while they are off.