What is "Trim"?

[hibbert6]

Boy, do I feel dumb, here, but my old Merc 650 has no trim control, so I'm not sure what people mean when they advise to "Trim it all the way down" or something like that.

I can manually set the tilt of the motor (a real difficult, 2-man job) and I've been putting the pin in the second hole from vertical, but there are about 5 more holes to try. That would aim the prop more "up" - what would that accomplish"?

Thanks in advance -

Dave

 

[Scaaty]

Re: What is "Trim"?

Boy, do I feel dumb, here, but my old Merc 650 has no trim control, so I'm not sure what people mean when they advise to "Trim it all the way down" or something like that.

I can manually set the tilt of the motor (a real difficult, 2-man job) and I've been putting the pin in the second hole from vertical, but there are about 5 more holes to try. That would aim the prop more "up" - what would that accomplish"?

Thanks in advance -

Dave

You are probably fine in the second hole. If its gets out of its own way easy coming on plane on a WOT punch, and a good sharp turn does not have the prop "cavitating"...(rpm's will increase)..you are in the catbirds seat...don't worry about it..

 

[tashasdaddy]

Re: What is "Trim"?

with a fixed motor, it is an experiment to the the motor at the best angle to the boat, to give you the best hole shot, and cruise attitude. you have to look for a happy medium.

where with power trim. you can lower the motor completely, to get out of the hole, and as the boat comes up you adjust the angle to the best cruise angle.

 

[MikDee]

Re: What is "Trim"?

The starting setting on maual trim is getting the cavitation plate paralell with the bottom of the boat, using a straightedge (whatever hole you need to put the rod in to get it closeest to that) if need be, favor the angle up a bit, for normal running. If you want to experiment, go up one hole at a time, and try it. As you go up each time, the bow will rise more, and the boat will take longer to plane usually, but it should take more boat out of the water, & go faster, you may get some cavitation in the turns as you go up, then you may get to a point where the prop will lose grip, & cavitate all the time (that's too high). It's a clunky system, with power trim, you can wait till the boats on plane then trim out to just before cavitation, and usually pick up a few more mph. Out of the hole will always be harder, and longer as you trim up, but with power trim it's simply push the button, bring it down, and start over.

 

[hibbert6]

Re: What is "Trim"?

Thanks, guys! So for pulling skiers & tubers, I take it "down" is best (parallel to the hull) but to boogie across the lake at top speed I should tilt the engine away from the transom as much as is possible without cavitation, right?

 

[MikDee]

Re: What is "Trim"?

Right!

 

[JCF350]

Re: What is "Trim"?

Thanks, guys! So for pulling skiers & tubers, I take it "down" is best (parallel to the hull) but to boogie across the lake at top speed I should tilt the engine away from the transom as much as is possible without cavitation, right?

Pet peeve!!!

There y'all go, starting somebody out wrong. The term is VENTILATION not cavitation. Grumble, grumble, grumble

 

[Outsider]

Re: What is "Trim"?

Ventilation, cavitation, BFD!

I think you'll find it easier to hit a happy medium between skiers and boogie and go about having fun without constantly screwing with the trim ...

 

[45Auto]

Re: What is "Trim"?

Once you've had a boat with power trim you'll never go back!!!