peteswaf

I'm very new to boating and I made a mistake. I had forgotten the previous owner of the boat said not to run motor with drive up. Ayways I did today and revved it too as it made a large vibrating clunking sound. The boat was on the trailer and I never engaged drive. I was just warming up motor and revving it and wondered what the sound was. Anyways, I lowered drive and noise and vibration stopped. I'm wondering if I damaged something and now what will prematurely fail. Should i have drive checked out? What do you think might be damaged?

Thanks guys

MOBILEMERCMAN

You probably didn't hurt anything, you heard your u-joints screaming.
Its good practice not to run it with the drive up all the way. The joints spin all the time the motor is running.
Jim

JohnnyG

First off, welcome! I'm pretty new myself around these parts, but there is a wealth of information on tap and lots of experience, which is why I like the place so much. I have a lot to learn still...

I started our first boat a couple of times in the trailer position and it always sounded real clunky until I lowered the drive. It was a bravo 1 x drive with 496HO. This is generally a no-no for the u-joints, but I never had any issues with that drive even after accidentally doing this a couple times. Just be sure you don't put it in gear in that position. I've read of more than one drive grenading from such behavior.

On the other hand, I've witnessed some pretty funny stuff at the ramp, including a guy driving off with his family with an alpha drive in the trailering position and wondering why there was so much water shooting in the air. Took him about 30 seconds or so to figure it out. Apparently, alphas are more idiot proof!

That was the same day a guy pulled his boat out of the water with the drive all the way down and dragged it across the concrete for about 20 feet while his wife was screaming at him. I should eat lunch next to the ramp on a busy day more often. Good entertainment. Ha ha...

John

Knot 4 Me

As others have indicated, it was the u-joints making noise. Probably no long-term damage done. Also, it is not a good practice to rev the motor up in the throttle-only position. Doing so could result in water being reverted into the motor.

Viper TT

On another note, did you have water flowing through the drive via a garden hose and adapter?

Make sure you don't run the engines without water.

peteswaf

VIPER TT

Yes I did have the hose and water turned on and connected. Thanks for being thorough.

MOBILEMERCMAN
JohnnyG
Knot 4 Me
VIPER TT

Thank you all for your responses... I appreciate it greatly.

Croozin2

Just a little note about running them on the hose. My local Mercruiser guy mentioned it to me when I first bought my Formula. A Bravo sea water pump moves an incredible volume of water for it's size. When you are running on a garden hose, it's usually not a good idea to rev the motor. If you watch closely, when you rev the motor it will actually suck a garden hose flat and could starve the sea pump possibly causing damage to the impeller. Even if it doesn't damage the impeller, the amount of water the garden hose can deliver is probably just barely enough to keep everything cool at idle or just above idle. Just to be safe, when on the hose, i wouldn't rev the motors. Some shop guys may disagree but that's the word I got from our local guy.

Viper TT

Croozin2 is absolutely correct. In fact, I think in the instructions for the Mercury adapters it does state not to exceed 1200rpms.

Knot 4 Me

I believe there was a TSB from Merc back in the early 2000's that revised their instructions for running a motor off a hose. If memory serves me, they actually wanted you to elevate the RPM to about 1,200 and not do any "throttle chops" to avoid water reversion. They claimed running off the hose at a normal idle speed of 650 - 700 RPM could actually result in water reversion.

Croozin2

That sounds reasonable too, especially on the "blue" motors that have more cam overlap. I guess I had stock engines on the brain at the time. But, you're right. If you run it up and chop the throttles that's prime territory for reversion. Good info!