Noise when Alpha Gear is In Forward

[milkyway]

I have my boat on a trailer and I periodically run the engine on the trailer while checking other things. The engine sounded norman by itself, but when I engaged the throttle to forward, to spin the prop at almost idle speed, then I heard this rattling, clanking noise with vibration, sounded like loose gears. This noise has been there for a while and I could boat without any problem. Any guess what this could be and preventive measures I should take?

 

[tommays]

Re: Noise when Alpha Gear is In Forward

is the drive all the way down<br /><br />its pretty dangerous to spin the prop on land<br /><br />on land there is no load on the drive but when the engine is running all the gears are always turning going into forward will engage the shift dog but its going sound different than in the water with no load on the prop<br /><br />tommays

 

[milkyway]

Re: Noise when Alpha Gear is In Forward

tommays,<br /><br />no, the drive was not fully down, probably 3 qtrs. out. this makes a difference i suppose. should this really matter? the drive is used to trim plane.<br /><br />so i suppose i should not be concerned at this point. <br /><br />thanks.

 

[djvan]

Re: Noise when Alpha Gear is In Forward

Probably will be winterizing pretty soon any way, should pull the drive (normal winterizing maintainance), check the u joints and grease (replace if they have play).<br /><br />DougV><br /><br />edit: this is mercruiser alpha one recommendation, other drives are not familiar to me.