Manual Trim Mercury 30hp

[gazza2006au]

I have a new boat which has a manual trim 30hp Mercury 1999, when the motor is trimmed at the 3rd hole in she digs the nose when trimmed in 2 holes she raises the bow enough for the ass to sink and be bow high, the last owner ran it on 2 holes in and put foils on it, it most deafinatly needs the foil because its running 2 batteries and 70litre fuel tank on a 4.6 meter tinny but in saying its size i think it was only ever rated to 30-40hp its an old De Havilland forward steer 2 seater

any idea how to go about fixing the trim? i really need the trim right between the 2nd and 3rd hole

[scottar]

Look into a trim and tilt unit - either genuine or aftermarket would be my first choice. Other than that weight distribution.

[Noelm]

That seems to be a rather big difference for moving it just one hole! I had a similar setup for years and moving it one hole made little difference.

[Noelm]

It's not a long shaft motor on a short shaft transom causing extreme differences somehow??

[gazza2006au]

Look into a trim and tilt unit - either genuine or aftermarket would be my first choice. Other than that weight distribution.

Those are quiet expensive i have previously looked at the CNC i think it was they are about $1000 thats half of what the boat cost me

It's not a long shaft motor on a short shaft transom causing extreme differences somehow??

It's long shaft on a Long shaft and the motor has been lifted around 20mm by a block of marine grade timber under the transom clamps, the hydrofoils are spot on level with the hull at the 3rd hole but with two blokes up the front she nose dives

its running 70 litre fuel tank and two normal size batterys so there is a little bit of weight on the ass end but i thought the foil would level it out

[gazza2006au]

Here's a couple pictures, one shows the foil level with the hull and the second one shows how the previous owner told me to run the boat with the motor up higher due to the nose digging in on the other setting

me and 2 mates took the boat out on the weekend with it tilted a little up in the second hole as the nose was raising, the motor was not reaching its full potential as in top speed but it was easy to get on the plane

if i chose the right setting and trim hole which is the 3rd hole do u think the hydrofoil is causing the nose digging? on my previous boat i had this same problem and it would cause violet left or right pulls almost capsizing due to the cheap nasty hydrofoil making the hull flop to one side of the bottom of hull in the V shape

[scottar]

The foil won't help if you are bow heavy already as it will lift the stern futher. Take it off and try it.

[Triple]

Is the foil clear of the water when on the plane in either position?

[gazza2006au]

I'll try it with the foil taking off but i suspect it won't go anywhere because of the huge fuel tank and two batteries at the back of the boat

the foil i believe would be just under the water probably by 10mm or so but the outside of the wings will be under the water because the boats hull is a V and the foils are horizontal or flat

does anyone know where to get a couple cheap tires from i have looked on Gumtree and Ebay seems hard to find 165/70/10, they are 10 inch tires and i have 4 stud 100mm pcd, need to replace these tires before i can workout the trim problems the tires have huge gaping cracks around 8 inches long on the walls

[robothefisho]

Put a plastic sleeve over the trim pin and get that sweet middle spot you want...

[Noelm]

Most tyre places will have 10" tyres, if not in stock, they can get them next day, that was a standard old Mini size. 70 litre fuel tank is probably on the large size for a 30HP, might pay to try a plastic standard tank for testing, or siphon the fuel out to remove some weight.

[gazza2006au]

I was going to test the tinny out yesterday when we encountered a nightmare scenario, i picked up a couple aluminium 10" wheels from gumtree yesterday morning and replaced the steel mini moke wide wheels and we were traveling along the M5 motorway tunnel in Sydney when we exited the tunnel city bound by 20 meters the left wheel feel off and over took the car doing an amazing balancing act on the barrier the other side of the barrier was a 30 meter drop but the wheel came back onto the motorway

a cop on a motorcycle pulled up within 2 minutes and a highway patrol within 5 minutes we were struggling to find a set of 8mm fine thread nuts to refit the wheel, we found 2x 8mm course thread nuts they held the wheel on for the approaching tow truck to tow us to safety

i had done up the wheel nuts correctly but i didn't realize the tiny 8mm bolts on the mini wheel hub didnt fit the holden wheel holes so after a juggling act in peak hour traffic 2 times to super cheap auto i had wheel nuts for the other side the correct nuts and i had a new hub on the side that fell off

5-6 hours later we were on our way home

boat never got tested

[pig75]

I put one of these on my old boat worked really well http://www.cmcmarineproducts.com/pro...or-up-to-35-HP

[gazza2006au]

Guys I'm back, the trim from hole 2 and 3 made no difference at all and unfortunately i have been too keen to hit the water i haven't had a chance to take of the hydrofoil but i just spoke with a guy from SOLAS and he recommended i run a 11P 4 blade propeller whats your thoughts on this?

[scottar]

4 blade props are generally used where extra stern lift is wanted. Removing the foil is still the next thing (not to mention the cheapest thing) to try in my opinion