97' Bayliner 5.7 liter Alpha Slightly overheating and bogs down to idle NEED HELP!

[Wheelman81]

Hello fellow boaters! I have a 97 bayliner 5.7 liter with merc. outdrive.This boat has never been in salt water. I have been having this problem with the boat bogging down to an idle (and dying if I try to run it faster after it has bogged) in the last three summers and have taken the boat to the shop 4 times now to have it fixed. I have had the fuel tank drained,water separator replaced,flame arrestor replaced,water pump rebuilt Now the mechanic is telling me I need to replace the thermostat and if that don't work then it is the manifolds which will be costly for a boat that old. I got the boat ten years ago from my father in law which bought it new and it is a good boat and has been well taken care of and maintained, it does not even have a rip in the seat. one of the mechanics from the shop which is a well known shop with a good reputation had to take the boat out on the lake to make it re-create the problem because it would not do so in the pit they use. I was told the fuel pressure was normal and it was running a little hot about 10 or 15 degrees and it was shutting it down as a safety precaution. I need any advice I can get please maybe the mechanic has overlooked something or maybe it is something small that he does not know about or a common thing to go wrong with this engine. Thanks in advance!!.

 

[Scott Danforth]

welcome aboard

start with replacing the raw water pump
then go from there

carbor EFI?

post a serial number

find a different mechanic

look at your fuel system for the power issue

take a look at the stickies, lots of information in the stickies

 

[Wheelman81]

Thank you Scott Danforth! I will post serial number and it has EFI. I know this is a dumb question but where do I find the stickies I am new to this as you seen and thanks for the warm welcome

 

[Scott Danforth]

go to the top of the forums. the top threads are "stuck" there. they have links and info. best to browse the site by computer vs phone.

with the motor being EFI, the mechanic should have plugged Rhinda or other into it to get real time data to help diagnose.

 

[Wheelman81]

Ok I found some Q & A's on the exact same thing that is happening to mine with the same motor only it is carbureted and mine is EFI. There were two responses to the questionand they were possible "fuel tank vent problem". With EFI could it still be a fuel tank vent problem? Also my mechanic said it was reading the proper fuel pressure while on the lake would it still read the proper fuel pressure with a vent problem. The advice of fellow members was to remove filler cap when the problem occurs and see if the bogging stops Yes Scott Danforth I agree 100% he should have hooked it up to a data reading machine of some kind and I am not sure if I should trust this mechanic he bought the business 4 years ago from previous owner and I did not know this until a week ago. I will be taking it to someone else from now on.

 

[Scott Danforth]

yes, if your reading proper fuel pressure, you dont have a vent problem.

if you have a vent problem, your fuel pressure would drop.

you could have a vapor lock issue as well.