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Loud whoosh noise at high rpm

MVHCmaniac

New member
I searched the web for something matching what I'm experiencing, but couldn't find anything close, so I decided to hop on a forum and ask you guys.

We have a Suzuki 250 outboard that's been treated pretty well for the seven years of its life. We flush it after each use, raise it completely out of the water between trips (it stays in the water over the summer), have it professionally winterized each season, and aside from electrical issues a few years ago, it hasn't given us many problems.

We're on the water now and something is very off. The motor sounded great when we started, and all the way through no-wake-zone speeds. When we accelerated from about 7 mph to 25, after a couple seconds it started to make a very loud whooshing noise. You know that noise you hear when it's really windy, like 40+ mph wind, and it blows over cables and poles and such? That's what it sounded like, and it wasn't coming from the boat. It was very loud, and definitely coming from the motor, most likely the lower unit. I didn't see a whole lot wrong with the wake; it wasn't getting a whole lot of water near the prop, but that's normal for us on plane. This starts around 3,000 RPM, 10-12 mph, and gets really loud around 4,000. After a little longer I could feel it kicking just a little bit. Not really kicking; the motor was running the whole time, but it felt like irregular slight lurches or bumps from 0.5-2 seconds apart. The motor doesn't seem to make any sound indicating these bumps/lurches, I can just feel it from the boat. Now, at lower RPM, just under 3,000, it sometimes vibrates a bit.

Concurrently, we're having issues with our jack plate, a porta-bracket. It's going up and not down. After some time it went down in bursts as we clicked the switch, but only about 1/3 of the way. I don't think that's the cause of the motor issue, as it started before we raised the jack plate and noticed that issue. Lowering it that 1/3 distance doesn't seem to have helped any; if anything it's gotten slightly worse.

Anybody have any idea what's going on here? We're still out on the water- we started about an hour ago and since the seas are pretty calm we decided to continue over to our spot, although moving at a low speed. I'm not sure how much longer we'll be out, but if it really does start to feel like it's too much to ignore, we'll probably head in- although I'm not the captain, and I feel like we hit that point a while ago.
 
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