Temporary Bad engine performance after hitting bottom

[Oldboater]

Here in the Bay at Ocean City, there are a lot of shallow parts, I have hit the sandy bottom a couple of times. I trim the engine up and get out of that area. I have noticed that a few times my engine performance seems to decrease, it "misses" at higher rpms after this. Now, it always has been fine the next day. The engine never overheats during or after one of these episodes. I do flush out my engine every time I take it out.

What could be causing this, is sand getting in coolant system?

[Oldboater]

30 views and NO COMMENTS ?

Is this that unusual ? (guess not everybody hits the bottom)

[HandymanHerb]

I hit bottom many times never lost power or hit the prop, my prop guard hits first and then I trim up to jet through low area's

[MIKEYLIKESIT]

i think the lake i go to (Lake Houston) is about 5ft deep in a lot of places with some really low spots and we ran aground a few times getting stuck once, but never really had any engine trouble from it. stirred up lots of mud, but it still ran ok.

[tkrein]

let me give it a shot how old is the motor give me specs cause if its older you might be loosing power due toi fuel issues but are you sure that you arenot picking up anything like weeds and have them causing some issues witht the prop.

[Oldboater]

let me give it a shot how old is the motor give me specs cause if its older you might be loosing power due toi fuel issues but are you sure that you arenot picking up anything like weeds and have them causing some issues witht the prop.

2009 90 HP Yamaha 4 Stroke with about 10 hours on it.

Now, once I went through weeds and had to raise motor, it acted funny for a while, but cleared up.

That was the only time I raised up the motor, maybe I should raise up the motor after hitting bottom to assure that nothing is on the prop? I will if (when) this happens again. When I get back to my dock, I have a lift and nothing is on the prop then.

[tkrein]

always after i hit a sandbar or something i will power down the motor raise her up and inspect the motor to see id there is any damage. you never know so you could of been draging something and dint know it.

[badmoonrising]

We have heavy SAV (Submerged Aquatic Vegetation) here on the Chesapeake, some species will wrap around the prop and make the motor feel like it's running rough, but what you are feeling is the imbalance caused by the tangled SAV on the prop. I put the motor in reverse briefly to clear it and head on my way....

[Oldboater]

We have heavy SAV (Submerged Aquatic Vegetation) here on the Chesapeake, some species will wrap around the prop and make the motor feel like it's running rough, but what you are feeling is the imbalance caused by the tangled SAV on the prop. I put the motor in reverse briefly to clear it and head on my way....

BINGO, I think you got it Badmoonrising ! Thanks for all the other replies also.

I have never lifted the motor after hitting a sandbar. It does seem like an imbalance when I try to rev the motor. AND when I dock my boat I reverse it, so by the time I lift it out of the water the SAV is gone.

Thanks for offering an explanation, I'm an Engineer and these things bother me when I don't understand what is happening.

[badmoonrising]

Yep, you'll feel even the slightest imbalance at the helm if there's SAV or prop damage. If something feels different it's always good to take a look.