Own a 40hp mercury 2stroke ouitboard motor can't get boat to plain out whats's up?

Question

Own a 40hp mercury 2stroke ouitboard motor can't get boat to plain out whats's up?

Answer 1

well it could be a number on items?

1- type of boat

2-weight in boat and positioning of weight

3-have you changed props? possible wrong size!

4-does the motor sound like it bogs down when u give it full throttle from the half throttle postion? If so it is your power pack.

5-if was your carbs then one you would have trouble starting engine or the engine would run crappy all the time.

6-did this motor plane boat b4?

7-have you bought fuel at a different location other than your normal location? poss bad fuel,drain and re-fill...

8-how long has it been for a tune-up? try replacing the plugs first this is a cheap first try because the power packs are expensive!!

all else fails take it to a marine shop.....

good luck!

Answer 2

If not running good>Plugs> Coil> Carbs> compression> Check and see which 1 is at fault>Check plugs see if firing>If so than fuel clean main jets carbs> Is the prop OK Not slipping> Or bent>

Answer 3

If it's an older 40 merc.....those we're notoriously sluggish engines. Long stroke....small bore...you can't get any revs outta them...

You might:

1) change the weight distribution in the boat.

2) Lower the tilt angle (does it have power trim?) if not, there is a pin on the back just above the transom mount...move it down a notch or two

3) Change prop....your probobly turning about 17-22" prop...go down an inch.

4) Make sure the engine is actually developing full power, is it running on one lung?.....

5) maybe your just pushing too big of boat....

Hope this helps.

with respect to the above...if a power pac is gone....you'll notice one of two things...

1) it's running on one cylinder....it'll be very hard to start and won't idle..it also won't get more than about 7kts outta it

2) it will 'hit and miss'....sudden power surges followed by abrupt cut-offs....

Before replacing pac....do the wires and plugs...the high tension plug leads are good for about 7-10 years....less in harse hot condtions..

Answer 4

HP to weight ratio might not be enough to shove your boat on plane. As the hull leaves the water, the amount of force necessary to move more hull out of the water increases exponentially with the surface area to be pulled out of the water until the boat is on plane, where the hp-to-weight ratio drops for a time with increasing speed.

A 4-stroke has a lower hp-to-weight ratio than a 2-stroke. The weight on the transom shoves the after part of the hull lower in the water, thereby increasing friction. The thrust of the engine pushes the bow out first, shoving the stern in deep, anyhow. You can try redistributing weight in the boat, increasing the output of your engine (see other entries), or repowering.

Answer 5

Check each carb. to make sure you are running on all cylinders.  Turn the s***w out on the side of the carb to check for gas.  Sometimes the little valve sticks and gas will not fill the bowl with gas.  If you find no gas in one bowl you will have to take it apart to clean it.