1998 50L will not go over 2500rpms no power

"Hello All,

I have been re

"Hello All,

I have been reading some info on this forum and find it very useful. I just bought my first boat a 1998 Maxum 2300sc with 490hrs this week, its powerplant is 5.0L Mercruiser with an Alpha 1 gen 2 outdrive. I am very new to boating, so sorry if i sound a bit ignorant on certain things.
Well i took the boat out on the lake for the first time yesterday, after getting the temp up to 170 or so i figured it was warm enough to start giving it some throttle. when i go past 35% it has no power at all, the fastest it would go was about 7mph with full throttle. When i put in neutral it revved fine passed 4K it felt like it had alot of power. with it engaged it would bog down and turn off at times. I did noticed alot black smoke noticed it was running really rich. I took some pics of what it was leaving behind. The owner of the boat assured me that it was in excellent condition and there was nothing wrong with it. I spoke to him from the middle of the lake and he suggested that i clean out the carb and it should be fine.
i am going to just do a whole tune up i am going to buy the following:
Plugs
Oil change
clean the carb out
change all fluids
Any other suggestions? any help would be great..Thanks In Advance.. "

"Welcome Rene:

Nice rich so

"Welcome Rene:

Nice rich soot trail on the water. Good evidence it is running too rich or you have bad gas that just won't burn.

"the fastest it would go was about 7mph with full throttle" What RPM was that 7 MPH? Could just be a slipping prop for that issue if the RPMs were above 2000.

"clean out the carb and it should be fine" That is a bold "it's your boat now so don't call me anymore statement". It may just be the choke is not opening up as the engine warms or the float and needle are off the setting and too much fuel is flooding the engine.

Change the oil, use Merc 25W40, Shell Rotella 15W40 or Mobil One 20W50 and stick w/a mercruiser filter. Pull the spark plugs which will be overloaded w/soot and install new.

Change all of the fuel filters.

Get a can of carb. spray cleaner and spray all the linkages, the throttle and choke plates and their bushings. Clean the flame arrestor from the inside out and dry w/compressed air. Next add a drop of light oil on the linkages and all 4 throttle and choke bushings.

Now check to see if the choke plate closes when you push the throttle a little while in neutral.
If it does, turn the ignition key to the RUN position and DO NOT START IT. W/in a few minutes the choke plate should start to open. If it does then that part is working.

Turn off the ignition for now. Hold the choke plate open and have someone give the throttle lever a quick forward movement. You should see two good squirts of fuel inside the car each time it is pushed quickly. If you do then you're down to the float setting. If not the accellerator pump is not working; needs replaced.

Next thing is to see if it is flooding. If you know what you are doing you could remove the carb top and check the float setting and/or replace the float and needle if it is off. If there are several things wrong w/the carb then either rebuild it or replace it w/a quality reman.

If you just want to see if it will run, then hook up the hose and ear muffs w/full water pressure and start the beast in neutral. I start my cold engine w/2 pumps of the throttle in neutral and turn the key. If it kind of sputters give it a little throttle up to 1200 RPMs. Never go over 1500 RPMs out of the water.

If it sputters and dies and won't restart immediately, take the flame arrestor off and look for fuel on top of the choke. If it's thers then the float is off and needs worked on.

Good luck."

"thanks for the info Guy, i wi

"thanks for the info Guy, i will let you know what happens i should get the part by Tuesday or so.."