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Author Topic:   Yamaha 40 HP
here fishy posted 09-16-2000 02:02 AM ET (US)   Profile for here fishy   Send Email to here fishy  
I have a 1978 13' whaler with a 40 HP Yamaha. I have electric tilt and trim. The motor has the "doel-fins" which supposedly helps with planing however I still "porpoise" quite a lot once I get to about 17 MPH. I don't have a tachometer or speedometer but I figure that's the speed it's begins to "bounce". I haven't floored it yet, so to speak, but I gather that the boat should be able to get to at least 25-30 MPH. I'd like to get to 17-20 without bouncing even in the sea conditions that I generally fish in which are 2-3-4 foot swells. Maybe I'm being unrealistic due to the size and weight of the boat but it's worth a try. The boat handles fine otherwise and I'm happy with the modifications I've made. I recently took photos and am considering submitting them for posting in Cetacea.

I'm not great with motors but I do know that the trim affects the ride of the boat. Once I lower the boat into the water I tilt the motor down until I hear the motor touch the "two pistons type" gadgets which I suppose are the trim rods. Once the motor rests on them it is practically perpendicular to level.

Is it advisable to get the motor further down beyond perpendicular? Does that require adjusting the trim? Will that get my bow down and help avoid some of the porpoising?

As I said earlier I'm not very good with motors but the trim adjustments can't be that difficult. There is a switch under there, also there is a manual screw which releases the trim. I also see some allen wrench fittings in the general vicinity of the trim mechanism. It's all new to me and I really don't want to start messing with things unless I know for sure that trimming down will help a bit.

Clark: I did get your emails. Thanks.

Any experiences, recommendations or suggestions would be appreciated.


Clark Roberts posted 09-16-2000 08:47 AM ET (US)     Profile for Clark Roberts  Send Email to Clark Roberts     
Gus, don't start messing with allen screws etc..!!! Check that the "pin" has been removed from the bracket adjustment holes... if there is a pin (rod that slides side to side through bracket holes) there, remove it! You are not getting enough "tuck-in" (motor won't swing close enough to hull)! If pin has been removed you may need to have wedges installed to compensate! What boat? A 13 has extreem angle on transom and should give plenty of tuck-in... let us know... Happy Whalin'... Clark... Spruce Creek Navy
here fishy posted 09-16-2000 12:51 PM ET (US)     Profile for here fishy  Send Email to here fishy     

The rod is not there. There is still room for the engine to tuck in. I'd say there is another 5-7 degrees of tuck available without harming anything or comming close to the transom. The trim hydraulics seem to be set so the motor rests perpendicular in lieu of the rod doing the support.

Could I release the position that is set and put the rod in so I could get more tuck?
What about the wedges you refer too?


Clark Roberts posted 09-17-2000 07:10 AM ET (US)     Profile for Clark Roberts  Send Email to Clark Roberts     
Gus, I would need an eyes-on and hands-on to really help you here... you need to grab someone out there in California who knows trim/tilt, outboards etc... get some local advice... something simple I would guess! good luck... and Happpy Whalin'... Clark
Lil Whaler Lover posted 09-17-2000 07:22 AM ET (US)     Profile for Lil Whaler Lover  Send Email to Lil Whaler Lover     

I agree with Clark that it may be simple. After very carefully rereading your first post, I am interpreting that you stopped the trim and tilt mechanism yourself at the end of the tilt range, "until I hear the motor touch the "two piston type gadgets" which I suppose are the trim rods". Have you tried holding the down button on your power trim to see if it will provide you with more tuck in? When the trim unit reaches the lowest level it will make a sort of ratcheting sound. this is not harmful as long as you relaease the button shortly after hearing it ratchet.

Also the tilt portion of the trim and tilt will move the motor fairly quickly while the trim portion will move it very slowly.

I suggest that you try holding the down trim position longer and see if it goes any lower. It sounds like you may have stopped at the start of the trim range. Godd luck, Dave

Clark Roberts posted 09-17-2000 09:15 AM ET (US)     Profile for Clark Roberts  Send Email to Clark Roberts     
I think Dave has it!!! Those two trim rods (pistons) should be fully retracted in "full down" engine trip position.... Clark
here fishy posted 09-17-2000 12:10 PM ET (US)     Profile for here fishy  Send Email to here fishy     
There you go fellas! I always stopped at perpendicular cause of the "ratcheting" sound. Naturally, I thought I would cause damage to the unit. Never did try to go a bit further to see what happens. I'll try it and let you know!!!


Ed Stone posted 09-17-2000 08:51 PM ET (US)     Profile for Ed Stone  Send Email to Ed Stone     
Someone said add a small dab of grease to
the strike points of those two trim rods
and that would stop some of the noise.
good luck!
I would think you should not have a problem
with your whaler hitting close to 40mph and
with proper trim stop the porpising.
here fishy posted 09-19-2000 06:23 PM ET (US)     Profile for here fishy  Send Email to here fishy     
Yes sirrrrrrrreeeeeeee!!!!!

Well, I was able to tuck the motor in just by allowing the tilt to push the trim rods further in. The rods naturally cause resistance and that's why I never went further. Once I get back on the water I'll see how the extra tuck helps with porpoising.

Thanks gents.


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