MacGregorSailors.com

Nose up, Put more weight in the bow/v-berth.

Remember, the cavitaton plate on the motor must
be located within one inch of the bottom of the boat.
The installer should have done it properly, (mine installer
did not) and I had to raise it. Gheck that before you go to
the trouble of raising the motor.

Hey Sorcha... we can hear ya just fine!

IS THAT WHAT THAT BUTTON DOES!!! ok..managed to buy and fit a 5 degree wedge plate. at the same time i raised the motor one hole..resulting performance still dissapointing..18 knots max at 5200 rpm again nil wind flat seas..the motor can probably still be raised more as i couldnt induce cavitation..ive got one hole adjustment left so i will try this next..also will try different props during next week.i should also mention i had 2 people on board and tried getting the second person to go right foward ..still only 18 knots...do i need more than a 5 degree wedge plate? again thanks all for your help.

Sounds like they gave you a de-tuned 90 or something. Maybe you better check the numbers on the block and see if its really a 50. Either that, or maybe one of your cylinders isn't running (does it sound right?). With just me on the boat, I can just barely hit 19mph with a 50 and I have a lot of junk in my boat as well as bottom paint. Something sounds fundamentally wrong with your setup. A bit of trim here and there shouldn't make that much of a difference.

you said you had a 15 pitch prop. That is too much. I said drop the pitch until you get the RPMs up to where the motor was designed to run.



Pitch should be around 11 or thereabouts depending on the motor. sheeeze. Go get the right prop, or be happy with what it is doing. You should also check the spark advance and fuel line.

the current pitch is 11inch .i have just learnt there is a way of checking how much power an outboard is giving.apparently there is something called a test wheel that is bolted on instead of the propellor and the max revs the motor gives with this fitted is checked on a graph which shows how much power is being developed.The consensus seems to be that this motor is only developing around half the power it should be ,so bombadier are giving me a test wheel to check the power output.by the way the computer check the evinrude dealer ran on the motor does not look at power output.Also i have just spoken with another owner with a 90 hp etec who is getting 29knots max.,so the 17 knots mine is doing is somewhat off the mark.

by the way craig max revs for a 90 hp etec is 5500 and the bombadier engineer say 5300 max is their optimum target.

oops, my bad.

I was thinking it was supposed to be higher rpms, but didn't look up your motor.

A Mac never goes faster than when brand new. These days with the extra bits and pieces + bottom paint don't get much more than 15 knots (18mph) flat out w/out ballast from the Merc 60 BF @6000 rpm WOT. Extra weight knocks off performance big time in these boats. Each extra adult = 1 less knot off top speed in my boat. Set up in full cruising mode with water, fuel, food etc for a couple of weeks don't see much more that 10-12 knots flat out.

Cheers,

AJ

I too have an M with a 90 ETEC and find the 29kts difficult to believe. Is it on an M or an X? My speeds are more in line with yours. 14x11....20kts. Now it will still do 17/18 loaded up, so I can't say I'm terribly disappointed, but I can't see it doing 29 with a 200 on it. My current thoughts are that the x is faster with the large engine and that the 70 and 90 ETEC produce the same results in this application. If I had to do it again, I'd save the $1500 and get a 70. I don't mean to be Debbie Downer, just relaying my experience.
Dan

Sounds like BWY is onto something when their testing with the M proved that a 70 was the one that fit the bill.

I think the size of the engine block matters also, as far as torque. My OB has 1600cc, the Suzi 70 is 1300cc, the Merc 50/60 is 1000cc, the Etec 90 has 1300cc.

If it is anything similar to motorcycles, bigger engine, more torque down under and I LIKE THAT A LOT

DGA wrote:I too have an M with a 90 ETEC and find the 29kts difficult to believe. Is it on an M or an X? My speeds are more in line with yours. 14x11....20kts. Now it will still do 17/18 loaded up, so I can't say I'm terribly disappointed, but I can't see it doing 29 with a 200 on it. My current thoughts are that the x is faster with the large engine and that the 70 and 90 ETEC produce the same results in this application. If I had to do it again, I'd save the $1500 and get a 70. I don't mean to be Debbie Downer, just relaying my experience.
Dan

I am willing to change from a 50 HP four stroke, Yamaha engine to 90 HP four stroke but as per your information, if 70 HP gives same speed as 90 HP, then why to spend more more. Do you really have tried both of these engines

yep i also find 29 knots difficult to beleive .the boat in question is an m and has just been sold.The new owner who i spoke to last night said it has a 13 3/4 by13 inch 3 blade alloy prop and the outboard height is such that the outboard bracket is 40mm above the top of the transom.Mine is about 60mm but its not cavitating so is still ok.This means my cavitation plate is about 40 mm above the extended line of the hull.The new owner hasnt yet tried out his boat but will next weekend and is going to let me know how it goes.Also the dealer here says that he sold another 26m with a 90 etec and that boat was doing 25kts with the original prop <mine did 15 to 16>.It will be interesting to try the test wheel when i get it and actually find out how much power my 90 etec delivers.Dont forget my boat is brand new with no bottom paint and zero junk inside.Will keep you posted.

Thanks dan for your comments .Im still hoping the boat can go a lot better.I guess Im hoping there is something wrong with my motor and it is fixed or replaced .The test wheel will prove all.