How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Charles Your Own Question
Charles, Marine Mechanic
Category: Boat
Satisfied Customers: 3979
Experience:  US Navy (Ret) Certified Mercury Marine Tech with over a decade of repair experience.
Type Your Boat Question Here...
Charles is online now
A new question is answered every 9 seconds

I have a 1999 Mercury XR6 2 stroke 150. I'm having a hard time

Customer Question

I have a 1999 Mercury XR6 2 stroke 150. I’m having a hard time getting it started later in the day, and then when I do get it started it bogs down and sputters when I apply power to get on plane. Even when warm and if only stopped for 10-15 minutes. In contrast, when I pump the ball in the morning it gets hard on like 2-3 pumps and the motor cranks right up. Late in the day, I’ll choke it and pump the ball, but the motor will just turn and turn and then hesitantly get started as if it’s not getting fuel, and then I’ll have the bog down feeling when I actually start to go. It will also idle real low and surge until I've run it a bit longer. Once I get the RPM’s up, it does just fine.
Submitted: 2 years ago.
Category: Boat
Expert:  Charles replied 2 years ago.
Hello, my name is***** you for allowing me to assist you today.
Has the engine been sitting for some time unused?
Have you tested the compression on the engine yet?
Customer: replied 2 years ago.
he engine came on a triton that I bought used roughly a month ago. The owner had not ran it 4 weeks prior to the purchase date. I have ran it every weekend since then. The owner had someone run a compression check and the motor had 124 on the cylinders. When I initially purchased the boat it was mid-spring and the weather was fairly cool. Highs in the mid 70's. The motor never gave me one minute of trouble. It would plane out at 5400-5600 rpms as the manual says it should. Started and idled fine. Once the weather started getting warmer, I started having problems in the afternoons. When the highs were above 85 degrees. rough idle with sporadic surges of high idle. Spits and sputters until on plane then it will run fine at the recommended 5600 rpms. If I take some throttle off though it will spit and sputter again. By the next morning it will be fine.
Expert:  Charles replied 2 years ago.
Is the engine really smoky when it starts?
How old is the fuel in the tank?
Have you removed and checked the spark plugs to see if any look a different color than the others?
Customer: replied 2 years ago.
yes the engine smokes when it is initially started. it quits once you give it some throttle. it had half a tank when I purchased it. I don't know how old that fuel was. First thing I did was added non-ethanol fuel and a bottle of sea-foam. I checked the spark plugs and the are all the same color.
Expert:  Charles replied 2 years ago.
Does the primer bulb get firm when you use n in the afternoon?
Have you added any fuel since then?
Customer: replied 2 years ago.
I replaced the bulb a few weeks ago and the new bulb gets hard if you hold it vertically. When the engine runs it is somewhat firm but not hard. I have ran the boat down to a quarter of a tank several times since then and have always filled it p with 93 non-ethanol. I also noticed when I replaced the primer bulb (attwood) that the fuel lines were attwood brand, which tells me they were replaced at some point by the previous owner as attwood is an aftermarket namebrand.
Expert:  Charles replied 2 years ago.
That is common on an older boat to replace fuel lines, they do go bad over time.
Can you drain the carbs and catch the fuel that is in them and see how much oil is in it? You will need to remove the air box to get at it.
Customer: replied 2 years ago.
I can't at this time but I can get around to it tomorrow. The motor does not have oil injection though. I run a 50:1 ratio and add 16 oz of oil to every 6 gallons of fuel. If that information helps you out any.
Expert:  Charles replied 2 years ago.
Yup that blows one thought out of the water. If you drain the carbs, check the fuel in them for water.
Customer: replied 2 years ago.
Ok I will check for any water in the fuel and get back with you tomorrow. thanks for the help.
Expert:  Charles replied 2 years ago.
No problem. Also take out the two bolts that hold the fuel pump on. Remove the outer hose and then use the primer bulb to see if you can see any fuel come from the outside nipple or the hole in the rear of the pump.
Customer: replied 2 years ago.
ok. I will definitely check that out also and let you know something.
Expert:  Charles replied 2 years ago.
Sounds good. I will be online for most of the day.