2000 islandia loss if power

[Bigal2369]

Hi everyone, I have a 2000 islandia with the mercury 240 efi m2 drive. I bought it a year ago, (our first boat)!! I always thought it under preformed , even after new filters and plugs. I was told ,and it appears true that this was a rebuild engine, and they had removed the oil injection and were running premixed 50:1 .This year I really tore into it and found water entering cylinder 1 , (bottom left). I found the head gasket seal cracked and letting water enter the cylinder. I replaced both head gaskets along with new bolts ,torqued to specs. I got it together and took it out. Ran great !!!!! Bet it has ever. The next day my wife wanted to take it on a longer ride, about 2 hours. On the way back it suddenly lost power . From 40 mph down to 15 . Limped it to my dock , it will start and idle fine , but as soon as you try to accelerate it just wont get up to speed. I pulled plugs back out and they look fine. Checked comp and at 125 . Changed all 3 fuel filters and even ripped out the vst tank to make sure it wasn't clogged. It was really clean actually. Please help , I dont wanna get rid of this boat, but it's becoming a pain in the butt. Haha

 

[Rubcuev]

I’m having the exact same problem with my Islandia. After a long drive or after towing a towable, I lose power and have to limp to the dock. So far I’ve changed the TPS and both coolant sensors. I also lose my Control Steering System when this happens. Changed out both reed switches on the Control Steering System. I’m hoping I can find the solution along with you.

 

[Bigal2369]

I’m having the exact same problem with my Islandia. After a long drive or after towing a towable, I lose power and have to limp to the dock. So far I’ve changed the TPS and both coolant sensors. I also lose my Control Steering System when this happens. Changed out both reed switches on the Control Steering System. I’m hoping I can find the solution along with you.

What year is yours?

 

[illru]

Is it high rpms going slow? I would look at the jet pump for damaged parts like the stator, swirl and wear ring. Or there is crap stuck in the inlet.

Or low rpms? Then I would look over the fuel system again. Starting with a pressure test of the fuel pump.

 

[Heatsink56]

What year is yours?

mine is a 2003 model.. im pretty sure it is the fuel pump.. thinking of taking it to my local merc dealer and letting them run a diagnostic on it for 140 bucks.... ( sorry i thought you were asking me please disregard, i'm a rookie. )

 

[Bigal2369]

Is it high rpms going slow? I would look at the jet pump for damaged parts like the stator, swirl and wear ring. Or there is crap stuck in the inlet.

Or low rpms? Then I would look over the fuel system again. Starting with a pressure test of the fuel pump.

Low rpms, I can get it to rev hi if I put in reverse, I'm thinking cause its cavitating. Back in fwd it's a dog

 

[Bigal2369]

Is it high rpms going slow? I would look at the jet pump for damaged parts like the stator, swirl and wear ring. Or there is crap stuck in the inlet.

Or low rpms? Then I would look over the fuel system again. Starting with a pressure test of the fuel pump.

Pressure test shows 35psi. Am I correct that it should be 49 psi? And do I start with the high volume pump in the vst, or fuel pressure regulator

 

[illru]

Pressure test shows 35psi. Am I correct that it should be 49 psi? And do I start with the high volume pump in the vst, or fuel pressure regulator

You should have 34 - 36 after the regulator. I would say your fuel pump is fine. Compression looks good...

Low rpms, I can get it to rev hi if I put in reverse, I'm thinking cause its cavitating. Back in fwd it's a dog

This is odd. Do you have out of the water? Look up into the intake and nozzle for any thing stuck in there.

 

[Bigal2369]

You should have 34 - 36 after the regulator. I would say your fuel pump is fine. Compression looks good...



This is odd. Do you have out of the water? Look up into the intake and nozzle for any thing stuck in there.

Compression 115 across the board. It's still I the water , I will take a look.