BigBendFishing.Net

I have a Mercury two stroke that is 7yrs old and it has been serviced regular. When I go from a dead stop to wide open it hesitates. Is this normal? Any ideas?
It has a new fuel filter and new plugs. Any advice other than getting rid of the Mercury?

Sounds like your fuel air mixture it too lean when you open the throttle. When the throttle is opened, more force is applied to to the fuel and air going into the engine; since gas is denser than air, it is takes longer to respond to the increased force and not enough goes in. Some engines have an extra pump designed to inject more gas in the engine during throttle increase to account for this hesitation. Sounds like that pump has gone bad in your motor.

i have the same problem with my 2005 90 2 stroke are you saying the regular fuel pump is going bad or is there an extra fuel pump for excelleration???

Your best bet would be to take to Fred @ Parkway Marine in Tally. He's the best Mercury mechanic around here and will get your problem solved.
There's no reason to get rid of the motor.

Is it an Optimax?

Dino 08 wrote: When I go from a dead stop to wide open it hesitates. Is this normal?

Yes it could be normal.
If you are slamming into gear the gears have to lock in fuel has to flow and the spark has to advance.
These actions will take a moment of time.
If you are already in gear and fast forward the throttle the hesitation will be less or non-existent.
How does it perform AFTER the hesitation?

I am not slamming it into gear. It is in forward and when I give it the gas it hesitates for a moment and then it goes. It is not an Optimax. I was hoping someone has had the same problem and it could be a easy fix???

DOWNTIME wrote:i have the same problem with my 2005 90 2 stroke are you saying the regular fuel pump is going bad or is there an extra fuel pump for excelleration???

The pump I am talking about is an extra fuel pump that just gives a short burst when you accelerate. It's called a diaphram pump on some engines. I am not all too familiar with boat motors so I am not sure if they have this extra pump.

I had a similar problem one time with my motor (mercury 40) but mine was fixed with some fresh fuel. Gotta love the ethanol. As long as I keep fresh fuel and use stabil i have no problems.

Nothing wrong with a Mercury.

What size is the motor? Is it an EFI motor or is it carbed? Either way it could be a number of things. Do you have a fuel/water separator? Have you checked your fuel lines for cracks? Have you checked the INSIDE of the fuel lines for deterioration? What shape is the primer bulb in? How much fuel pressure do you have? Have you checked the fuel filter under the cowl? These are a few of the simple fixes.

It could also be a fuel delivery problem, or an ignition problem, or a bad reed, or..............

If you don't solve the problem yourself Reel Cowboy gave you some good advice. Take it to Fred.

If you have EFI most likely the injectors will need cleaning. When cleaned the boat will run like brand new. I have a guy in Naples , Fl. that can clean them cheap. He helped me with my Yamaha 115 4 stroke 2004.

Thanks for all the advice. Carried it to the shop this morning. Will let you all know the outcome.

tin can wrote: Reel Cowboy gave you some good advice.

You sound surprised TC.

Paint dat motor white and it will get right to work. lol ... j/k

Reel Cowboy wrote:

tin can wrote: Reel Cowboy gave you some good advice.

You sound surprised TC.

Update....
Carried the Mercury to the shop and they adjusted the carbs. They made it run richer. It is running like a new one.
Thanks for all the advice.

GLAD YA GOT HER RUNNIN RIGHT. WHEN SOMETHING LIKE THAT HAPPENS GENERALLY ALL YA HAVE TO DO IS LOOSEN THE CAP ON THE FUEL TANK AND IT WILL STRAIGHTEN ITSELF OUT. ANOTHER THING TO CHECK IS THE FUEL PUMP ITSELF, THEY WILL CRACK WITH THIS ETHANOL GAS WE ARE GETTING NOW. ALWAYS PUT STAY-BIL OR OTHER CONDITIONER IN ADDITION TO THE REGULAR FUEL OIL, THE FUEL SHOULD BE 50-1 RATIO, IF IT HAS BEEN SITTING FOR A LONG TIME THE GAS WILL EVAPORATE AND GIVE YA A MUCH HIGHER RATIO OF OIL TO GAS. IF IT HAS NOT BEEN RUN IN A WHILE, SAY 6 MONTHS OR SO, EMPTY YOUR TANK AND USE THAT GAS IN YOUR LAWN MOWER, PUT IN FRESH GAS WITH THE PROPER AMOUNTS OF FUEL OIL AND STABIL OR OTHER CONDITIONER, BE SURE THE GAS TANK CAP IS LOOSE AND SHE SHOULD RUN LIKE NEW.
PA
SEMPER FI