Help with 2007 yamaha 90TLR 4 stroke

[frfghtr895]

Anyone ever had similar issue with this motor? My previous mechanic's comments "Diagnose hard starting, stalling and erratic idle. Computer diagnose found intake passage fault. Checked for intake leaks and none were found. Noticed idle speed control not functioning (diag monitor shows 60% open). Checked wiring continuity from ECU to ISC and there were no open or shorts. Commanded ISC to fully open and it did not. Checked TPS and linkage adjustments both in range and not the cause of the ISC issue. Suspect ECU to be the cause of the ISC not functioning but ISC Valve had been replaced already which did not fix the problem" So his adviced was to take it to yamaha dealer so they can test the ECU. His temp fix was to advance the throttle valve. The issue only happens if i quickly shift to reverse while launching the boat and the motor stalls. If it does stalls i have to high idle start the motor in order to get it to run. Also sometimes RPMs rev up and and stay around 1100 so I have to shut it off and restarted in order for the motor to act normal. If i started and the RPM's go back to normal idling then the motor has no issues. Any advice would be greatly appreciated.

[boscoe99]

We need to hear in your words what the problem is that you are having with the motor. And, when you are having the problem.

What parts, if any, have been replaced?

The F90 EFI Yam has a known issue where the wire harness and connector can get damaged. I would start with first checking the wire to the socket connection within the ISC valve connector.

The ECU tells the ISC valve what it wants it to do. If it can't talk to the ISC valve that can be a problem.

[frfghtr895]

We need to hear in your words what the problem is that you are having with the motor. And, when you are having the problem.

What parts, if any, have been replaced?

The F90 EFI Yam has a known issue where the wire harness and connector can get damaged. I would start with first checking the wire to the socket connection within the ISC valve connector.

The ECU tells the ISC valve what it wants it to do. If it can't talk to the ISC valve that can be a problem.

Pretty much if at anytime my engine stalls when I put it in gear, mainly launching the boat from the trailer by myself, the engine does not want to start unless I do it on high idle. Once it starts then I can turn it off and it will start back again on neutral with no problems. Other times when I start the motor the rpm's stay around 1100 and in order to lower them I have to turn it off then on again once or twice in order for the rpm's to go back down to 800. So we could replicate the stalling problem and put it on diagnostic computer but couldn't track the actual cause. What I initially posted were the actual notes from the invoice. He checked all the wires and connectors and everything looked fine. The only thing he could come up was that the ECU was going bad.