Mercury, SeaDoo Islandia 2003...Help Please!

[Storage]

My 2003 Islandia, 2 Stroke 2003 Mercury 240 EFI
...did not rev over 1,600 rpms, and has NO Throttle Guardian! First Mercury Dealer, kept ALL last Summer, 5 mos, and said his Computer... showed EVERYTHING...>Normal! Could Not repair, SO I took to 2nd "Country Man" mechanic that is Older, and works on ALL outboard engines! Kept ALL Winter, and in early March..... he got the engine to Rev up another 1,100 rpms, to 2,700 rpm.....but Sputters & engine dies over 2,700.... He Gave-Up! 3rd.. Took to SeaDoo Dealer March 23rd, and emailed Svc. Mgr. 23rd April.... he replied, saying his Mechanic said the engine was a Mericruzer, but STILL had on scheduled for Service last week in month. Today 2 Months LATTER (3 Months total) I went over and my boat had NOT been moved 1 inch, from where I left it in March, so I brought it home! I am 100% Disabeled Vet, and am so FRUSTRATED that I can not get in the Engine compartment to check wires myself, as from ALL (hrs & hrs) I have Searched.....it appears that the Port side "Temp Sensor" may be the issue, as I read it will PREVENT the engine from Reving up, if sensor registers..>. as still being COLD......which makes sense, 2nd, I read that the REV LIMITER may be the issue, and that if the ECU, is ... DisConnected,,,,, that Engine will Run WITHOUT it! If this is TRUE, can some one tell me where & COLOR of Wire, ....to Temporarly disconnect it ...." to determine if "Electrical" is the issue? Dr Honda, .......AnyOne have advice? Thank you...... Bill

 

[Dr Honda]

Did someone tell you it can run without the ECU? It's a fuel injected engine... there's no way to make it run without a computer. That is... unless you want to put on a set of carbs, and a magneto ignition from an old outboard.

The temp sender won't keep it from reving up. The worst it will do is make it run VERY rich.

So... you need to figure out if you are losing spark... or losing fuel. BUT... since you say it dies over 2700rpm... I'm going to say you have a fuel problem. But... how did your guy get that extra 1100 out of it? What was he working on? That would be the clue on where to start.

 

[Storage]

Did someone tell you it can run without the ECU? It's a fuel injected engine... there's no way to make it run without a computer. That is... unless you want to put on a set of carbs, and a magneto ignition from an old outboard.

The temp sender won't keep it from reving up. The worst it will do is make it run VERY rich.

So... you need to figure out if you are losing spark... or losing fuel. BUT... since you say it dies over 2700rpm... I'm going to say you have a fuel problem. But... how did your guy get that extra 1100 out of it? What was he working on? That would be the clue on where to start.

Dr Honda....... Thank you for that info. The repair Shop Cleaned the injectors, to get it up to 2,700. The boat had been sitting for 5 years when I purchased it, and was 80% full of (Old) fuel, which owner said he had added Fuel stabilizer. It ran for about 2 hours the first time in Lake. I stored it up over Winter, and when put in water next Spring the 1,600 rpm problem began. I made a note to myself a few months ago.... That ECU >..." Adds 5 deg of timing when the engine is cold. (Below 3000 RPM)"
IS this statement true concerning the ECU on the 240 EFI engine? ... Would 5 deg of advance possibly cause this?
2nd..... and this is a long-shot..... "could the pick-up hose in fuel tank" be restricting Fuel supply?
Thanks Again!

 

[LikeabossTM]

Get rid of that fuel, it's far too old and is likely a cause, or THE cause of your issues. Anything over a year old WITH stabilizer starts to degrade, losing the ability to combust and likely dropping a few or more octane points as old as what you've alluded to.

Probably you want to have your fuel system serviced again afterward as well.

 

[Tim75]

Replace at least the first 2 fuel filters also. There is a strainer on the bottom of the fuel pickup in the tank.

 

[Storage]

I have again "Looked for the Throttle Guardian" .....behind steering console, as I thought the previous owner must have cut it loose, but I cannot see the 2 holes where it was Mounted, or ....ANY loose wires,... from it having being previously wired-in at the console! IS there >...ANYWHERE else that SeaDoo would have placed this "Throttle Guardian"? .... I have tried for hours to find a wiring diagram... so I could trace the wires from the engine to the TG, but seems that... BOTH Sea Doo and Mercury do NOT have the "TG" shown in any of their wiring diagrams! I would think it unusual for Sea Doo to have NOT installed the TG on this one Islandia!
....AS 2 seasoned Mercury mechanics, with over 50 yrs experience, can-not find anything wrong in their engine diagnosis, I want to find this.. TG! ... .....Thanks!

 

[Dr Honda]

That ECU >..." Adds 5 deg of timing when the engine is cold. (Below 3000 RPM)"
IS this statement true concerning the ECU on the 240 EFI engine? ... Would 5 deg of advance possibly cause this?
2nd..... and this is a long-shot..... "could the pick-up hose in fuel tank" be restricting Fuel supply?
Thanks Again!

Adding timing to the engine at idle will cause the RPM's to be higher so it won't stall.

Yes... the hose could be restricting fuel... but that's not how the engine works. The fuel system feeds a vapor tank, and it feeds the high pressure system. SO... if there is an issue would fuel... check the pressure at the regulator.

As others have said... 5 year old fuel is DONE. drain the tank, and replace the filters.

After that... I would put in-line spark testers on all 6 plugs, and make sure you are firing on all 6 plugs.

 

[Storage]

Adding timing to the engine at idle will cause the RPM's to be higher so it won't stall.

Yes... the hose could be restricting fuel... but that's not how the engine works. The fuel system feeds a vapor tank, and it feeds the high pressure system. SO... if there is an issue would fuel... check the pressure at the regulator.

As others have said... 5 year old fuel is DONE. drain the tank, and replace the filters.

After that... I would put in-line spark testers on all 6 plugs, and make sure you are firing on all 6 plugs.

...........Thank you..... also have 6 New Plugs n 6 Wires on the way next week!
.......... BTW..... Can not find where the Throttle Guardian was ever on this Islandia, No cut wires behind the Console.... Do you think it could have been Mounted....somewhere else on this Boat? Any idea where n the TG wires connected at the Motor? .... Thanks Again!!

 

[Tim75]

...........Thank you..... also have 6 New Plugs n 6 Wires on the way next week!
.......... BTW..... Can not find where the Throttle Guardian was ever on this Islandia, No cut wires behind the Console.... Do you think it could have been Mounted....somewhere else on this Boat? Any idea where n the TG wires connected at the Motor? .... Thanks Again!!

Not all boats got a TG.