2002 240 mercury sluggish then stall Help

[V6 Speedster]

Hello all very happy to be a new member of the site lots of great information very helpful people.
Here we go picked up a 2002 240 efi mercury speedster going to do a full restoration would like to know the best recommended spot to get all replacement sensors, filters etc..
it was a little rough tidied up the wiring tightened loose nuts and bolts got it running off the hose sounded strong so from there put it in the harbor for a trial rip, throttle doesn't seem to start engaging till just under half, Is that normal? seemed to be sluggish getting on plane then at full throttle stalled, Had to put it in neutral and it starts at idle did the same process and the same thing. Any ideas on what I could be checking to get it tuned or what this could be would be much appreciated? Thanks in advance

 

[rsatina2002]

Check your throttle cable if it needs adjustment... Also buy a manual here for 240 EFI Mercury handbook and probably you have a generation 1 engine check your serial number. Here in California nobody touch them, because of discontinued parts, I learn to DIY through the manual, through this forum, very helpful specially with Tim75 and Dr. Honda but can't find Dr. Honda anymore so Tim is very helpful for 240 EFI Merc engine.... There is 3 fuel pumps in this engine, mine I replace my VST electronic fuel pump through non-OEM parts but still firing very good at this time... Test your TPS, port side temp sensor. I think probably throttle linkage is your problem but check it in the manual too and buy it here but make sure first your engine serial number so you can buy the right manual for the engine. Mercury is very good in illustrating and testing and troubleshooting this engine. Thank you. Keep writing question so we can help you more.

 

[Tim75]

Is your flywheel cover round or square-ish?
This engine should rocket your boat out of the hole.

Need 2 people- one at throttle one at engine looking at throttle linkage. Move the throttle and check for movement. You should be able to tell where the "lost motion" is. Problem could be at throttle lever or engine linkage. These cables do wear out; they are standard marine cables; just need the right length.

Check the shift cable at the nozzle. Move bucket up and down. Listen for crunching/grinding sound. Same test for steering, except move the nozzle side to side. Again- standard cables.

Key on engine off--- check fuel pressure at schrader valve on top of the vst. Should be 36psi.
Key off--- open vst drain screw, side near bottom. Be careful-it's only brass. Should get gas with some oil. Close it.

Ignition--need a spark tester or 6. Are all the plugs firing under load? Running on the hose does very little for testing. The engine needs to be under load.

Fuel injectors-- 17 years of use/dis-use. They could use service. Cleaners don't work. You need to remove them and have them serviced. I had mine done a couple of years ago and wish I had it done 6 years ago. Better performance and uses less gas.

Checking the tps when having problems is SOP. It controls fuel/air from idle to about 2/3 throttle. Lots of threads here an testing. Stupid crazy expensive part.

Have you checked/replaced spark plugs? Use only oem NGK. While the plugs are out, check the compression. All plugs out, WOT. Pull emergency kill switch. Looking for 130psi or better.

Some boats have a throttle guardian that was to limit rpm. When it failed, it could cause all kinds of crazy stuff. If you have it, it should be in the helm box, near the steering box. Look for a black wire with yellow stripe. Disconnect it and test again.

Check wires coming out from under the flywheel. Harness of 6 wires. They are the trigger wires that tell the computer when to fire spark plugs. The original wires had really crappy insulation that crumbled over time. Check wire pairs with ohm meter. May need to replace the trigger. Need the proper flywheel puller from ebay.

At least now you have a little bit of testing to fill your spare time. Keep us posted.

 

[V6 Speedster]

That's awesome Thank you
I want to order a kit of all filters and sensors to replace them all any suggestions on who to contact?
Was at it a bit tonight found a rock between the impeller and guard lucky enough it jammed in only one little chip on impeller was able to get the guard off and rock out, the back four bolts are seized can I just do an oil change from the allen key holes if I flush it well? The back two slotted ones, was only able to loosen one, no oil came out,, other is seized not stripped yet but close,, Gonna take some thinking to get that one out sucks Can I put some heat to it?
Flywheel I think this is the proper manual
Should I be doing the oil delete been seeing trouble with the oil gear.

 

[Tim75]

You have a Gen 1 engine. Gen 2 has an alternator and an electric oil pump.

The 2 slotted screws are the oil change screws.
I have used a small scissor jack to jam a large screwdriver into the slot so the screwdriver can't cam out. Turn the screwdriver with vise grips. If you still don't get oil to drain, stick a small allen wrench into the holes to break the goo. To change gear and stator oil, you will need 2 quarts of Mercury/Quicksilver high performance gear oil and a small hand pump. Both from WalMart. As for a parts source, many on this forum use Crowley Marine. I use BAM Marine, (100 miles from me). Many parts on ebay.

You may be better to find a Canadian source.

I have been using the oil injection for 10 years. No problem. Your call.

If you have the flywheel cover, I suggest installing it. The flywheel looks kind of like a buzz-saw to me.

(My father's family came from PEI a hundred years ago.)

 

[V6 Speedster]

Ya good idea i'll try the jack, I had a good flat blade and channel locks one stuck maybe a little heat to.
That's awesome you ever visited witch part of the island I have an aunt in Sarasota
You must have changed the oil pump gear already?
I have the cover just off to tidy it up and work on.