Figured title might get some results much needed. I am a decent mechanic but getting old and forgetful. Here is my problem, I put my boat in the water (2001 Larson cabrio 254) last month and noticed that I couldnt get over 4000 rpm I also noticed a high pitch whine from the fuel pump. I changed the fuel cell after being towed back to the dock. I used a after market pump package and new filter. All lines are clear and tight. Boat idles all day at 600 rpm. Once you advance throttle engine will hold a rpm for a few seconds then fall back to idle. It then starts to surge from idle to where you have the control lever set at. Example 1800 RPM. Will surge back and forth and TBI sounds like it is sucking a lot of air. Doesnt make that sound till it starts to surge. If i return the control lever to idle shut the engine off and restart it will idle at 600 again all day long. once you advance the throttle it will start surging sometimes so bad it stalls. Items replaced so far in the last 30 days.
1. fuel cell hi low pumps
2. Injectors (qty 2)
3. distributor cap and rotor
4. plugs
Items cleaned
1. IAC looked good
2. fuel regulator internal to TBI holds pressure.
This sounds like it is starving for fuel once you advance the throttle will occasionally backfire too. Fuel pattern from injectors looks even and very good strength and spray pattern. I want to check the new fuel cell pressures but cant find fittings to attach to the volvo low and high pump ports (still looking). I would appreciate any help given. the boat has 375 hours on it and I have owned it for 5 years and never had issues. Ideas??????
1. fuel cell hi low pumps
2. Injectors (qty 2)
3. distributor cap and rotor
4. plugs
Items cleaned
1. IAC looked good
2. fuel regulator internal to TBI holds pressure.
This sounds like it is starving for fuel once you advance the throttle will occasionally backfire too. Fuel pattern from injectors looks even and very good strength and spray pattern. I want to check the new fuel cell pressures but cant find fittings to attach to the volvo low and high pump ports (still looking). I would appreciate any help given. the boat has 375 hours on it and I have owned it for 5 years and never had issues. Ideas??????