HELP! DT65 power loss

[hotdog]

Good morning, been helping my mate out with his engine, its a dt65 1997, it starts and runs fine on the muffs and in the water, revs up in the water too no problem, now when in the water in forward gear it would only get to around 2500-3000 rpms and would stutter a bit then stall but would start straight back up no problem then it would cruise along for a few minutes throttle wide open but only reaching 2500-3000 rpms but with the odd stutter? we have put on new impeller, new plugs, new coils, new fuel pump, new filter, checked all fuel hoses, tried different fuel tank and primer bulb, i have taken the carbs off again for another clean and inspection but look spotless? would faulty reed valve cause this? not sure if its a fuel issue as it only reaches a certain rpm, compression was 110-115 on all three.
Thanks in advance.

[Solarman]

Have you tried pumping the fuel bulb while running to see if it makes a difference? What do the plugs look like after idling around and running?

When cleaning carbs, make sure you remove and inspect the needle valve seat, for each carb, to see if any trash is blocking fuel flow. Identify anything you find. There are clear plastic discs, check valves in the fuel pump just before carbs, these have been known to fragment, and lodge on the backside of the needle valve seats. Once the seat has been removed always re-adjust float settings. Always use compressed air to blow through all pas-sages with clean paper towels to catch whatever blows out. Identify all trash found. This could tell l you if you have other items breaking down that need replacement.

The next step.
If you have a manual for that motor, check and test the stator/magneto leads by the manual. You may have a problem with the "high condenser charging coil"? This is one of the coils on the magneto that is needed for higher rpms.

Good luck, post back on what you find out.

[hotdog]

OK thanks yes I have a service manual, I have ordered some compressed gas today, I will check that out, just seems something more than a fuel issue, what else would make it go into limp mode? Also when my mate first put the battery terminals on to start it blew the fuse? Could that have maybe damaged cdi? Thanks for your help much appreciated.

[hotdog]

Also it revs up fine when the gear linkage is removed would the charging coil allow this or just under load it doesn't work properly?

[hotdog]

And I tried pumping the bulb too think it just flooded it as it gave out a sneeze, the plugs where a little coloured too.

[Solarman]

Yes, hooking up battery incorrectly can blow fuse"s". Check them all.

An air compressor is all you need to clean small carb pas-sages. Compressed gas will work if you don't have one.
Re-read middle paragraph about where blockage might be? Identify any trash found - important!

If there is a restriction of fuel, then at higher rpms (in forward gear) fuel will run out and motor will stall. Yes it will restart and run again, until the same thing happens.

You should NEVER rev a motor higher than 2000 - 3000 rpms in neutral!!!

Do you have a gauge saying it is in limp mode? What are the codes it is displaying?

Good luck.

[hotdog]

No guages saying limp mode just 1 guage on his boat at the minute, oil, Rev, temp guage, yes I will do as you said about the compressed air, just it seems to cruise and one speed and not get any faster as the throttle handle is pushed down that's why I was wondering about limp mode but I think there would be a buzzer going off if it was overheating or oil flow sensor? Thanks again.

[Solarman]

When cleaning carbs, make sure you remove and inspect the needle valve seat, for each carb, to see if any trash is blocking fuel flow. Identify anything you find. There are clear plastic discs, check valves in the fuel pump just before carbs, these have been known to fragment, and lodge on the backside of the needle valve seats. Once the seat has been removed always re-adjust float settings. Always use compressed air to blow through all pas-sages with clean paper towels to catch whatever blows out. Identify all trash found. This could tell l you if you have other items breaking down that need replacement.

If you have cleaned the carbs properly, removed every jet, and removed the needle valve seat, and reset float and mixture screws properly, and cleaned every tiny pas-sage thoroughly, then there may be other areas to inspect.

Good luck, post back on what you find out.

[Hoosmatroos]

Don't forget to synchronize the carbs afterwards.

[hotdog]

Still need some help guy's, nothing has worked heres what ive done so far, changed ht leads, new spark plugs, replaced fuel pump, filter, checked all hoses, changed complete stater magneto plate, changed cdi, cleaned carbs and reset them, what else could cause this? gearbox maybe? under propped? i have ran out of ideas! thanks in advance.
Regards, Simon.

[hotdog]

Would the throttle position sensor cause this or a fault in the wiring harness?

[Solarman]

Yes the next steps would be to check the gear counting coil, and the TPS. If you find any differences from the manual then swap it out. The gear counting and the TPS control send the signal for the timing by the CDI unit, depending on where the throttle positon is, with respect to the rpms given by the gear counting coil (This is why the distance of the gear counting coil is very important, it had to read and send the signal properly.).

The lower unit, does not control the running of the motor, likewise the same with the prop. Neither should cause hesitation of the motor.

Good luck, post back on what you find out.

[hotdog]

Thanks again, I will swap tps and check gear counting coil.

[hotdog]

No luck, changed tps and checked gear counting coil with feeler gauge, took the boat out and it throttles up no problem to about 2500-3000 rpm and cruises at that, then give it more throttle and it stalls? if you were to put money on the fault ignoring all the things that have been done what would you say? thanks in advance.

[2014DF25ARS]

I had an older 3-cylinder Evinrude that started running with limited top end. Turned out it was only running on two of the three cylinders! Sounded normal to me, but wasn't generating full power. We found that the head gasket was blown, leaking water into one of the cylinders and keeping it from firing normally. Do all three of your plugs look the same after running the motor?