Boat accelerates slowly

I am new to boat ownership and still working out the kinks. Not sure if the boat is supposed to do this, but lately when I accelerate, the motor sounds like it has a bogging sound to it. I can put the shifter 3/4 of the way up on accelerating but there's no push. It gradually increases as the boat is running. I can see my speedometer go from 3mph to 12 mph over a period of a few seconds as it gradually increases. This isn't normal right?

Once its running, it runs top notch, motor sounds good and I'm going 30mph with no hesitation. Its just the startup part. Maybe I should let it warm up a little bit more at the ramp? any ideas?

throttle cable

Make, model, year for boat and motor would be helpful. EFI or carbs?

2002 Kenner 18v-90. Motor is a Mercury Saltwater 90hp. Only used it last 8 times in freshwater. It has Carbs I believe. If its the throttle cable, am I better off having a mechanic look at it?

YES

Ok let’s get you working.
First let’s make sure you’re doing it right.
Trim angle all the way down?
Pop it in gear. Never try to ease it that will shorten the gears life.
Trim down moving forward you hammer the throttle to wide open. If you’re not doing exactly that you’re doing it wrong.
If you are doing exactly that I want to know what your rpms are at full throttle full trim.
You could easily have the wrong prop. If so it’ll never run right.

Good info Pat. So when I bought the boat, the RPMs gauge was not working. Still doesn't. However I guess I have been doing it wrong. I have it a full trim down, pop it into gear, idle till the breakers then I push it up to about halfway, then gradually increase it to full throttle, which is about 30mph on the water.

I took it out to the lake today to run it around and see what it feels like. So if I punch it, the engine seems to choke. Almost like its gasping for something, however, after about 30 seconds, it works it way up. Once it going around 13-15 mph, I push the accelerator up all the way and it adjust and now Im full zoom. I can kind of hear the bogging while its going but it feels solid.

Could it be the fuel lines? Primer Bulb? The gasoline doesn't stay in the fuel holder(filter?) I have to squeeze the bulb and then choke it to start everytime otherwise it cranks then doesn't even start up.

Or maybe the fuel?

I just filled up and added 50:1 2 stroke oil into the tank as well. Should I be adding some kind of cleaner or something to it?

Literally a hundred possibilities. But the basics.
Any gas older than six months is junk.
If you have to re-prime the bulb it's bad.
Check for any other fuel line leakage.
That motor came with an oil tank under the cowling. Unless it was removed, you shouldn't need to add oil to gas?
A can of seafoam to every tank of gas makes your motor happy.
So...
Replace the fuel line from the bulb to the motor. Make sure it pumps up hard and stays hard.
Look at your prop and tell me what it has written on it.
That's a cool little boat with a very rugged motor, let's get it running like it can.

Thanks again Pat. A few questions. Pardon me as they may be dumb since I am a newbie.

I do constantly have to pump the bulb. It is almost always loose and has no pressure unless I squeeze it. Does that relate to the fuel filter in the motor? I press the bulb and I can see the fuel enter the filter but then it drains back down. It doesn't stay there. Is it supposed to stay there?

The previous owner did say he removed the oil to where he could insert oil after each tank of gas, which for this motor, is 50:1.

I will buy seafoam and start using it from now on on each tank of gas.

I just bought the fuel line assembly kit. I figured I may as well replace the whole thing? Am I going to much into it here?

Prop says M9323 and also has a 16 on it.

The previous owner has a water hose plug in and that how he would flush his motor. He recommended I do it that way too. Would it be better to use the bunny ears or the regular hose. The plug has a leak in it when I test run it at the house. So I do need to replace that for sure. When I ran it on the lake, it leaked a lot of water into the boat, so I had to leave it facing out.

I would replace all the fuel lines and pull the carbs and put in new needles and seats along with fuel pump diaphram. Might be dumping too much fuel if floats are off. Definitely want to open up the thottle all the way when getting on plane.

Oh man.
You got stuff sticking out all over.
No idea why previous owner would disable the oiler it’s very reliable.

If you’re running freshwater lakes there’s no need to flush your motor. The flush hose should have a fitting it screws down to. That ends water spray.

Not sure what prop that is but a sixteen should be a rocket holeshot.

If you want to run the motor on the hose you need the muffs. The flush hose does not wet the water pump and you’ll burn it up in twenty seconds. Big no no.

All outboards should always run the spin on water separator filter. Gas is just junk today.

If it’s still a turd after fuel hose you might need a skilled pair of eyes on it.

Ok so ill buy the bunny ears.

I'll add some seafoam tomorrow.

Also, I have the fuel line assembly, so should I replace the whole thing or just from the bulb to the motor?

You've got the tank under the console model? If you can get to it, replace it all with ethanol resistant tubing.

Your challenge is if some bass pro genius tie wrapped your fuel hose to the rest of the harness through the rigging tube.

Change the fuel filter, also where the fuel line goes into the block remove the should be 4 screws and clean that filter with wd40. It's just a screen but it will clog up over time.

Thank guys. I haven't been able to work on it yet, but hopefully by the weekend. Lets see how it goes.

Ok I actually had some time tonight after all. I replaced the fuel line kit from the filter to the primer and to the motor. Seems like the vacuum filter in the motor is holding fuel now. Bulb didn't go soft either. I will check on them tomorrow afternoon after work.

Also, I went ahead and put seafoam and ran it like the directions said. Ran it for 5-7 minutes then turned it off. Then ran it again for another 5 minutes. My question here is it cleaning the motor now because the 2nd time I turned it on, the motor ran at a higher rpm obviously loud and started smoking out of the exhaust. Wasn't sure if I was burning something or if that's the seafoam cleaning it out. The flush ears were on correctly and still pissing a good stream. Just had me curious on that smoky and smell after the seafoam.

I will check all these things again tomorrow pending replies.

You said "lately." So it hasn't always done this, correct?

Correct. As in the last 2 weeks. But never before. I did fill up the tank since I was going to be using it vigorously here in the next month, but Ive never added any additives or anything to it, until the seafoam tonight.