Engine Position

[JubJub]

I took my boys for a ski today and its the first time I have given the new boat a good blow out.
I noticed when turning that the revs increase ( I presume thats what you guys refer to as cavitation) It has a cav plate on it but I feel the engine needs to be lowered. It can go down one hole to drop it about an inch. Would anyone advise against trying this to sort it out.

Thanks in advance and Merry Christmas to all

[Seahorse]

what size boat and motor

[JubJub]

Its a 4.75 Quintrex with a 75 merc

Overall it just doesnt feel quite right. Trimmed in it pulls to the right quite a bit then trimmed out to correct that and it porpoises . I am only new to boating but it seems to me that its a mounting issue

[blaze]

need to trim between them 2 points, thats the sweet spot. If you are only gettin cavitation on turns the answer is to trim in slightly on the turns and then trim out once the turn is compleeted. It sounds like the hieght is about right, if you drop it down a hole it may increase drag and decrease fuel economy, but maybe worth a try
merry merry chrismas
must stagger to bed
blaze

[fishin_till_late]

same thing happened when i was skiing with mates on wednesday. only in a 12 ft tinny with 25 hp, we mucked around with the trim holes and eventually got it rite. cant remember which one thogh but im sure its a common problem.

[JubJub]

need to trim between them 2 points, thats the sweet spot. If you are only gettin cavitation on turns the answer is to trim in slightly on the turns and then trim out once the turn is compleeted. It sounds like the hieght is about right, if you drop it down a hole it may increase drag and decrease fuel economy, but maybe worth a try
merry merry chrismas
must stagger to bed
blaze

Thanks for that. The cavitation is only when cornering but trimmed right in.

[Seahorse]

got my 30merc on 3rd hole out. like power steer. put hydrafoil on and will be testing out tomorrow,

[JubJub]

Mine is on the second hole from the top. Dropping it one more will lower in about an inch. Its only 4 nuts to undo so its worth a try

[JubJub]

Well I dropped the engine down yesterday and went for a run in the boat today and I am amazed what a difference it made. The boat is handling 100% better and I am really happy. I would never have thought an engine mounted 1" lower would make such a difference.

[Spaniard_King]

Jubjub,

I assume it's the original setup from a dealer ::)

Dealers don't often set boats up correctly. Good to hear you have made an adjustment and it worked [smiley=thumbsup.gif]

Garry

[JubJub]

Thanks Gary, it really suprised me what a huge difference a minor adjustment made. This is my first boat so I have a lot to learn but even to me it was obvoius somthing wasnt quite right. The guy next door has a forklift so it was pretty easy to lower it using the fork to take the weight.

If anything its taught me to be careful when making any adjustment to the engine because it could quite easily make a big difference in the wrong direction