2008 merc 3 litre bogging issue.

hotshott

Cadet
Joined
May 23, 2013
Messages
12
Hello everyone and thanks for letting me into your forum. I own a 2008 Bayliner 185 BR. 3.0 litre Merc. I/O Bought new and stored indoors during the winter. (climate controlled). The boat and motor has 57 hours on it. Oil and all other fluids are changed every year. Distributor cap and rotor are Mallory marine grade so as not to deteriorate quickly due to moisture. ignition is electronic. A syphon port was installed on the fuel cell so no fuel is left in the tank during storage. While prepping for another season and running in the driveway, (elephant ears on and water supplied to motor), When I lower the throttle to WOT, the motor bogs almost to the point of dying before beginning to take fuel and rev up where the RPM should be in relation to the Throttle lever position. The boat has an extended warranty but I have had the boat in for warranty work twice in the past and the minor issues were never repaired until I fixed them myself. As I now have absolutely zero faith in a warranty that I paid for, I am turning to the source of information that I should have done in the first place. Distributor timing is set at 2 deg. ATDC which is right where it should be. Fuel filter has not been replaced and I have an electronic fuel pump to replace the stock as merc/GM are notorious for a very poorly designed fuel delivery system. The only adjustments on the carb are idle speed. Mixer screws are capped as the motor is the ultra efficient model. Any and all help would be appreciated and thank you all again for reading.
This is the first (and last) I/O I will ever own. I own a 1998 Tracker 190 with a Johnson 75 O/B. This boat sits outside every winter.( covered). Some years with fuel in tank, some years without. EVERY season I throw in the Batts, Prime the fuel bulb and turn key start. Ignition was upgraded to electronic. Best motor/boat combo I have every owned.
 

greekfreek

Petty Officer 2nd Class
Joined
Jul 5, 2010
Messages
141
Re: 2008 merc 3 litre bogging issue.

Not knowing very much about your carburetor, but guessing that the accelerator pump on the carb if it has one, is bad... Whats a "syphon port" on fuel cell??
 

bonzoscott

Senior Chief Petty Officer
Joined
Jul 26, 2008
Messages
745
Re: 2008 merc 3 litre bogging issue.

You need to find another shop. Call around and see what they offer. The one you have is definitely not the one. Completely unfamiliar with an '08 motor but if it is carbed, like Greek said, probably accelerator pump in the carb.
 

2005bay

Cadet
Joined
Apr 15, 2012
Messages
18
Re: 2008 merc 3 litre bogging issue.

Are you sure you're not delivering too much fuel pressure with the electric pump and causing the needle not to seat and deliver too much fuel? That's the same symptom I bad on almost the same boat. My problem was the float was not set low enough (1-2mm adjustment did it). Same problem different cause.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,465
Re: 2008 merc 3 litre bogging issue.

Fuel filter has not been replaced and I have an electronic fuel pump to replace the stock as merc/GM are notorious for a very poorly designed fuel delivery system. The only adjustments on the carb are idle speed. Mixer screws are capped as the motor is the ultra efficient model.

Ayuh,... The mechanical fuel pumps have been workin' Perfectly for 50 years, or more...
Donno what yer talkin' 'bout with that comment....

You've got a fuel delivery issue,...
The fuel Filters should be the 1st things checked...

It sounds like you've got a "TKS" carb,... I agree, That's a problem,...
It also sounds like it needs Rebuildin'....

Yer fuel removal system is still leavin' gas in All of the fuel system, But the tank....
Hence, I'm guessin' the carb is boogered up...
 

hotshott

Cadet
Joined
May 23, 2013
Messages
12
Re: 2008 merc 3 litre bogging issue.

Not knowing very much about your carburetor, but guessing that the accelerator pump on the carb if it has one, is bad... Whats a "syphon port" on fuel cell??
It was installed by myself. I drilled a 2 inch hole into the top of the fuel cell, a 1 3/4 filler neck was plasti-welded to the fuel cell and cap installed. My fuel filler hose has an anti-syphon devise in it and I cannot get a syphon hose into the tank to remove the left over fuel. At seasons end the fuel is removed from the self installed syphon port. After which the motor is run dry, Fog cylinders, fluids removed, ect...
 

hotshott

Cadet
Joined
May 23, 2013
Messages
12
Re: 2008 merc 3 litre bogging issue.

Are you sure you're not delivering too much fuel pressure with the electric pump and causing the needle not to seat and deliver too much fuel? That's the same symptom I bad on almost the same boat. My problem was the float was not set low enough (1-2mm adjustment did it). Same problem different cause.

The electronic pump is a direct replacement for the Merc. 3.0.It was purchased from a friend of mine that races boats for merc. marine corp. Nice gig. It is not a high performance pump but exact replacement for the mechanical. It is a plug and play style and no customizing needs to be done. The fuel line was removed and fuel pressure is normal. I removed the carb and found it to contain some of what appears to be varnishing throughout. Not bad but surely enough. I have ordered the rebuild kit and the carb was delivered to Denna Marine to be hot tanked and blown out.
 

hotshott

Cadet
Joined
May 23, 2013
Messages
12
Re: 2008 merc 3 litre bogging issue.

Ayuh,... The mechanical fuel pumps have been workin' Perfectly for 50 years, or more...
Donno what yer talkin' 'bout with that comment....

You've got a fuel delivery issue,...
The fuel Filters should be the 1st things checked...

It sounds like you've got a "TKS" carb,... I agree, That's a problem,...
It also sounds like it needs Rebuildin'....

Yer fuel removal system is still leavin' gas in All of the fuel system, But the tank....
Hence, I'm guessin' the carb is boogered up...
First off, I have been building and racing hot rods for 4 decades. Mostly GM. Never had any luck with a GM mechanical fuel pump. In relation to my comment, It is my preference. I have owned a boat and motor of some sort for most of my life. Always an outboard. The 08 Bayliner is my first inboard as well as my first new boat and it has had it's share of problems. The carb is a TKS and the only other adjustments on the motor are timing and idle speed. I have removed the fuel line and pressure is more than plenty. Also the carb was removed and it appears to have a bit of varnish inside. The fuel filter on this motor is in the carb which has been replaced over the holiday weekend. The rebuild kit has been ordered and the carb is being hot tanked and blown out. It will be a week or two before results are in. I will keep you posted and thanks for the advise.
 

greekfreek

Petty Officer 2nd Class
Joined
Jul 5, 2010
Messages
141
Re: 2008 merc 3 litre bogging issue.

Like the idea of the syphon port. I tried to get a hose into my tank via the filler hose and was a no go...wonder if I could just tee off the fuel pickup line. Anyhow good luck and keep us posted..
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,465
Re: 2008 merc 3 litre bogging issue.

First off, I have been building and racing hot rods for 4 decades. Mostly GM. Never had any luck with a GM mechanical fuel pump. In relation to my comment, It is my preference. I have owned a boat and motor of some sort for most of my life. Always an outboard. The 08 Bayliner is my first inboard as well as my first new boat and it has had it's share of problems. The carb is a TKS and the only other adjustments on the motor are timing and idle speed. I have removed the fuel line and pressure is more than plenty. Also the carb was removed and it appears to have a bit of varnish inside. The fuel filter on this motor is in the carb which has been replaced over the holiday weekend. The rebuild kit has been ordered and the carb is being hot tanked and blown out. It will be a week or two before results are in. I will keep you posted and thanks for the advise.

Ayuh,... For the few bucks they cost, get yerself a spin on canister type water sep. filter, 'n mount it up-stream of the fuel pump,...

That keeps all the crud outa the carb, 'n the fuel pump....
 

hotshott

Cadet
Joined
May 23, 2013
Messages
12
Re: 2008 merc 3 litre bogging issue.

Bond-o, I have taken your advise and purchased the water separator for in-line application. I have not yet installed it as I am putting the boat on the water this Saturday with the fresh carb rebuild and will reset distributor timing and test under load. The guy who deep tanked my carb says he blew out copious amounts of debris during the process. He even offered to install the rebuild kit for no charge. I let him do it. The only thing bad about that is I am saving the money but loosing the knowledge. Sooner or later I will need to rebuild it again.
 

hotshott

Cadet
Joined
May 23, 2013
Messages
12
Re: 2008 merc 3 litre bogging issue.

Like the idea of the syphon port. I tried to get a hose into my tank via the filler hose and was a no go...wonder if I could just tee off the fuel pickup line. Anyhow good luck and keep us posted..
Greekfreek, The syphon port is nothing more than a fuel fill neck with cap. I got thru Grainger. It needs to be impervious to corrosive fluids, IE gas/oil/antifreeze ect... I drilled an 1 3/4 whole about half way thru the tank and finished the cut with a fresh box cutter blade so I did not get debris into the fuel cell. There are numerous adhesive/sealants on the market for this application but I opted to have the marine dealer do a permanent install by a process called plasti-weld. It is solid and does not leak. After looking in the manual, It states that syphoning of fuel from my boat is almost impossible as it has an anti-syphon devise to guard against theft. I use a small transfer pump and a battery op drill and it takes only minutes to empty.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,465
Re: 2008 merc 3 litre bogging issue.

Bond-o, I have taken your advise and purchased the water separator for in-line application. I have not yet installed it as I am putting the boat on the water this Saturday with the fresh carb rebuild and will reset distributor timing and test under load. The guy who deep tanked my carb says he blew out copious amounts of debris during the process. He even offered to install the rebuild kit for no charge. I let him do it. The only thing bad about that is I am saving the money but loosing the knowledge. Sooner or later I will need to rebuild it again.

Ayuh,.... Then you probably know, the rebuild has 'bout a 50/ 50 shot at Success,...

Ya probably oughta start lookin' for a replacement carb,...
 

hotshott

Cadet
Joined
May 23, 2013
Messages
12
Re: 2008 merc 3 litre bogging issue.

To all of you gentlemen who posted advise/tips I thank you. The boat is running beautifully and all as a result of a handful of advise from fellow boaters. I was able to get my wife out onto the water for a 2 hour ride and that is important. We are thinking about trading the boat for a pontoon. I have researched pontoons for a couple of years and would love to trade up to a 2 or 3 year old 24 footer. I know that some are priced through the roof, However I would love to own a pontoon over the boat. Skipper Bud's in Madison Wisconsin has a huge inventory of used pontoons. Has anyone out there used Skipper Bud's and if so how was your experience with them??? Thank you again fellow boaters.
 

BRG25

Chief Petty Officer
Joined
Jul 13, 2001
Messages
528
Re: 2008 merc 3 litre bogging issue.

So what was the problem????
 
Top