Looking for some assistance / recommendations troubleshooting an issue I'm having. My boat is a 2005 Bayliner with a Mercruiser 3.0 I/O. It has the TKS carb.
The boat will start just fine when cold. The TKS unit seems to be functioning properly. I can hear it hiss when cold. Then as the engine comea up to operating temp (175F) the TKS will shut off and the rpms will come down. I let it warm up in the slip until the TKS is off and then pull out into a no wake. Boat idles in gear and runs fine through the no wake. Boat will initially respond to throttle and get up on plane just fine. Runs great at 1/2 throttle to wot.
After boat runs for a little bit (10min or so) if I pull back on the throttle such as approaching a no wake zone the rpms will bog down and it will stall. It happens around 1/4 throttle position. Put it in neutral and it will start right up and idle as it should. At rhus point the boat will idle in gear and navigate a no wake. If i try going slow, 1/4 throttle, approx 1500 - 2000 rpms it will bog and stall. Boat will run great when going wot down to cruising at about 2500 rpms.
I've done all the basics:
Ruled out bad gas. Syphoned the tank empty and filled with known good gas and fuel stabilizer.
Check filter near fuel pump and inline filter at gas line connection to carb.
Verified good spark.
Installed new cap and rotor.
Checked, cleaned and gapped plugs. Plugs were new last season.
Replaced vent line from carb back to fuel pump.
Disassembled and cleaned carb. Carb was completely rebuild prior to last season and ran great all last year.
Adjusted idle speed and mixture (with special tool for mixture adjustment) per service manual procedure. Boat idles great in slip when warm after tks is off. Idle is smooth at about 850-900rpms in neutral. Idles smooth in gear at about 650 -900 rpms. I know thus is slightly higher than spec but this is where it idles smoothest.
Visually verified power valve shoots a good stream of fuel into the carb when throttle linkage is operated.
I set the float height and drop when assembling carb. Measured the throttle rod to spark arrestor flange per spec as well.
So the question is what am I missing?
Could i be chasing a vacuum leak? Did i maybe miss something when reassembling the carb?
I just ordered another carb rebuild kit. Could this be something other than the carb? I would greatly appreciate any suggestions for troubleshooting items to look for!
The boat will start just fine when cold. The TKS unit seems to be functioning properly. I can hear it hiss when cold. Then as the engine comea up to operating temp (175F) the TKS will shut off and the rpms will come down. I let it warm up in the slip until the TKS is off and then pull out into a no wake. Boat idles in gear and runs fine through the no wake. Boat will initially respond to throttle and get up on plane just fine. Runs great at 1/2 throttle to wot.
After boat runs for a little bit (10min or so) if I pull back on the throttle such as approaching a no wake zone the rpms will bog down and it will stall. It happens around 1/4 throttle position. Put it in neutral and it will start right up and idle as it should. At rhus point the boat will idle in gear and navigate a no wake. If i try going slow, 1/4 throttle, approx 1500 - 2000 rpms it will bog and stall. Boat will run great when going wot down to cruising at about 2500 rpms.
I've done all the basics:
Ruled out bad gas. Syphoned the tank empty and filled with known good gas and fuel stabilizer.
Check filter near fuel pump and inline filter at gas line connection to carb.
Verified good spark.
Installed new cap and rotor.
Checked, cleaned and gapped plugs. Plugs were new last season.
Replaced vent line from carb back to fuel pump.
Disassembled and cleaned carb. Carb was completely rebuild prior to last season and ran great all last year.
Adjusted idle speed and mixture (with special tool for mixture adjustment) per service manual procedure. Boat idles great in slip when warm after tks is off. Idle is smooth at about 850-900rpms in neutral. Idles smooth in gear at about 650 -900 rpms. I know thus is slightly higher than spec but this is where it idles smoothest.
Visually verified power valve shoots a good stream of fuel into the carb when throttle linkage is operated.
I set the float height and drop when assembling carb. Measured the throttle rod to spark arrestor flange per spec as well.
So the question is what am I missing?
Could i be chasing a vacuum leak? Did i maybe miss something when reassembling the carb?
I just ordered another carb rebuild kit. Could this be something other than the carb? I would greatly appreciate any suggestions for troubleshooting items to look for!