Hey, give a quick intro on the boat/motor
1995 Robalo 1820
08 optimax 150 sn# 1b692183- 200hrs
Going for a combine weight (ppl/gas/gear) a little over 4000lbs so I have a mirage plus 14.75, 17pitch prop
Here's the issue I was out running Wot (5400rpm) for about 5 mins when I felt the motor lose power and dropped to 4800rpm, trimming it I get a max 4950. The following day I notice that it would stall when I turned it on but if I put it in neutral and kick it up to around 650-750rpm it would stay running and not stall. When I shift it to gear it'll stall if I don't quick kick it up to 700-1000rpm.
Run smoothly from 700rpm-2000rpm. When it hits 2000rpm the motor starts to shake and sound weak and as I shift forward cant feel any power I guess like a dead spot. It kick up at 3000-3750 rpm and get on plane quickly but I can get it to go pass 4950 rpm. Also when I shift into reverse I need to shift all the way down to get the motor to react.
I've check compression all 110-115, change spark plug, water pump, poppet valve, thermostats, fuel filter. While the engine was on I pulled the DI plug and each one causes the engine to slow till I plugged it back. I used an inline spark tester on all the coils & all sparked. Check the fuel/air pressure 88/78
Could it be a bad tps, injectors? any help would be a Big help
Thanks