Hey guys, hoping I can get some help here..
I’ve got a 94 mercury 200hp xri efi, I noticed it started to get on plane slow slow slow, and now it won’t plane most of the time. When I hammer down it will start to bog down, but if it does get on plane it runs fine at wot. But once I come off and fish it’s a hit or miss if it will go. Idles fine and revs fine. I’ve never had an issue until this year.
I’m wondering if it could be a failing fuel pump, I’m replacing all the gas lines this week. Compression is good on all cylinders.
I’d appreciate the help!

I think you're going about it the right way. Starting with fuel lines is not only smart but this TFF'er thinks that's your problem. If those are original then ethanol has had time to delaminate them. Ask me how I know.

Should I go ahead and rebuild the fuel pump?

See what happens after you change the fuel lines. That may be all that's needed. One step at a time. Good luck.

Replace fuel lines and primer bulb from tank to pump.

When was the last time you had your injectors cleaned and flow tested?

It’s been 6 years, not sure how often you need to do it. I will be replaying all the fuel lines Friday.

I’ve taken it to a shop and they wanted to clean them for 600! And be put 6 weeks, I’m no mechanic but wouldn’t it affect its top end speed if they weren’t synced?

i second this

I would do fuel lines and do fuel pump and see what happen the lift pump get week from all this good gas we have also

No. Unlike the newer direct injected motors, EFI motors inject into the crankcase.

Well no luck with the fuel lines and new fuel pump kit

Make sure you are getting good spark on all cylinders

Injectors should be cleaned & flow tested every year or 100 hours whichever comes first. Southern Performance Injectors in Friendswood Tx.

Check the fuel pressure while running to make sure its in spec for that engine. Also, see how long it holds pressure after shutdown.

Southern Performance Injectors in Friendswood Tx.$25 per injector & about 10-14 day turnaround

I see you’ve been having this issue since 4-19? Those motors are some of the BEST Mercury ever produced. Maintenance is the big key! They'll last a long time & give trouble free service for a lot of hours IF you’ll do it. Contact me on PM if you want. I can give you some tips on it. They’re one of my longtime favorite motors. They’re little sweethearts if ya treat em right

Or you can clean the injectors yourself. Get a can of sea foam, a 12 volt battery, a momentary button, some 18g wire and an air compressor. Oh. And a piece of 3/8id hose. There are lots of videos on how to do it. It does a decent job.

You will likely need to change filters too.

My Yamaha 4 stroke needs this done around once a year or 100 hours. Whichever comes first. I know it’s time when I lose a couple mph and planing takes some effort. I have a spare set of injectors I bought from Amazon for cheap. I clean them at my leasure and swapping them on a Yamaha takes about 5 minutes start to finish.

Also...it could be spark plugs. Do NOT cheap out on plugs. Get NGK plugs. Not the super iridium or platinum junk. Just the exact OEM quality plug the motor calls for.

I guarantee you cleaning injectors, new plugs, and maybe new filters will have that boat jumping on plane.

Dirty injectors will slightly lower top end speed, but they will demolish your ability to get on plane. Your boat needs that torque to get that hull up and out of the water.

Also, this hot humid weather will have a noticeable impact on a outboards power. Some motor/boat combos are so bad that some owners change props between warmer and cooler weather.

Really, mine are 18yrs old and haven't been touched

Injectors should be cleaned and flow tested after cleaning to ensure satisfactory operation. Several injector cleaning services will tell you what order to install them in based on flow after cleaning and testing.

I have it going to the shop next month, I will let y’all know what the issue was when I get it out!