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View Full Version : Loud whistling noise from engine compartment. Weeds!....HELP!


brettmess24
07-06-2010, 10:30 AM
Brought the boat back to the landing and opened the engine cover and there was a pretty loud whistling noise from the engine compartment, only when in gear forward or reverse and less than 2500 rpms.

Got the boat on the trailer and behind the prop was covered in weeds on the shaft.

The raw water intake had weeds stuck inside the clam shell cover and when I got the boat home the water cooler screen was full of weeds as well.

So Im guessing my impeller at minimum is shot and that the sound was from air being pushed instead of water into the engine cooler.

The temp never got past 160 but the boat was only on the water for max 20 minutes.

The loud whistling only came when in gear at slow speeds.

Does this sound like just an impeller or could the weeds on the back of the prop caused more damage to bearings, races, etc?????????

Ordered new impeller and fake a lake but not sure the boat should be put in gear out of the water.

HELP!:o:confused:

Nvrgvup
07-06-2010, 11:33 AM
If it only happens in gear then I would suspect something in the drivetrain.

Inspect for weeds, stuff, fishing line around the strut bearing and where the shaft exits the hull. Check the prop and see if everything seems tight. Give it a good look over, clean it all up and move everything manually before starting it up.

Spin the prop shaft around and see how it feels. The strut bearing will squeal if it is dry so you may want to get it wet since it is water lubricated. It may have just had so much crap around the strut bearing it caused it to squeal.

You can pull the top hose on the raw water pump and look at the impeller. It is really easy to open it up and replace the impeller especially if it hasn't been done in a while. Don't get too aggressive tightening the cover bolts since they're treaded into brass.

The impeller may of overheated or gobbled up some weeds however I don't think it pulled in air unless there is a leak or it was running out of the water.

You can put it in gear however I wouldn't do it for long or fast and you will need to keep the strut bearing wet with someone spraying water on it. Just be careful. Personally I don't like to put in gear out of the water, that's just me.

The fake a lake is good. Since I was cheap I just pulled the intake hose and stuck it in a 5 gal bucket and put a garden hose in it. My wife just made sure the bucket had water in it and didn't overflow. I was surprised how much water it pumps even at idle. My garden hose was just barely keeping up.

Hope this helps.

brettmess24
07-06-2010, 02:20 PM
That does help a little, thanks.

I did turn the prop by hand and it feels good with no unusual noise or grinding feel.

I took the hoses off the housing but have not removed the cover to inspect the impeller. Should the impeller spin freely in the housing while in neutral? Am I looking for busted splines?

FrankSchwab
07-06-2010, 03:44 PM
The impeller isn't going to spin by hand in any way, shape or form. You're looking for broken vanes on the impeller, but a lot of times they won't be visible while the impeller is in the housing - you may see a big chunk out of the middle of the vane where the ends look just fine.

Pull the four brass bolts out, spray some dish soap in, bump the engine over, then pull the impeller. If you have a new one in hand, you can grab the old one with a pair of vise grips and pull, or you can use two paint can openers to lever the impeller out. As Nvrgvup noted, the screws are brass, screwed into brass. if you tighten them too hard, the screw heads will twist off, or the threads will strip. Be careful.

/frank

brettmess24
07-06-2010, 04:44 PM
The impeller isn't going to spin by hand in any way, shape or form. You're looking for broken vanes on the impeller, but a lot of times they won't be visible while the impeller is in the housing - you may see a big chunk out of the middle of the vane where the ends look just fine.

Pull the four brass bolts out, spray some dish soap in, bump the engine over, then pull the impeller. If you have a new one in hand, you can grab the old one with a pair of vise grips and pull, or you can use two paint can openers to lever the impeller out. As Nvrgvup noted, the screws are brass, screwed into brass. if you tighten them too hard, the screw heads will twist off, or the threads will strip. Be careful.

/frank

Thanks. That makes sense. So it could be that the impeller is perfectly fine even though it passed a few weeds? I suppose its good precaution to just change the $35 dollar part anyway. Or atleast flush the intake hoses and run the fake a lake.