1998 mercury 150 hp bogs down under load

[plumber1]

When livewells are full it takes forever to get on plane. Also when loading boat on trailor it stalls the motor completely out. Forgot to mention that it is on a Triton 18' bass boat. Sporadic idling when in gear. Any help please.

 

[Maxz695]

Re: 1998 mercury 150 hp bogs down under load

plugs come to mind first of all do maintenance wire (Coil) and electriccal such as dist cap if you have one. check compression to be safe

 

[j_martin]

Re: 1998 mercury 150 hp bogs down under load

Max, with all due respect, you don't need to guess when you don't have a clue.

Obviously it's sick. There's a sequence to figure it out.
1. Do a compression check, just to ascertain if the motor is mechanically sound, or not. If compression is poor, there is no "tune" thing you can do to fix it.
2. Do a spark gap test. If you have a good (7/16") spark on all 6 at cranking, then you can assume you have a fuel problem.
and so forth.

If you want to try to figure it out, we can help along the way.

hope it helps
John

 

[Maxz695]

Re: 1998 mercury 150 hp bogs down under load

he,s the one without a clue I appriciate your intelligence J thats why he,s here to get opinions and advice but i don,t have the motor here i,m simply stating (PROBABLE Causes for this happening not a fact no disrespect but any help is better than none at all. This site is blessed to have great minds like your,s here.

 

[jeffersondodson561]

Re: 1998 mercury 150 hp bogs down under load

How long has this been going on? Obviously you need to verify engine condition. Water is extremely heavy unstable. If everything checks out, I would suspect that prop size is a concern if this has happened all along. Being that your loading up on accessories/gear I would rig with a prop that at wide open you would be able to hit 5850-5900 rpms with no water/gear in the boat just you.

 

[j_martin]

Re: 1998 mercury 150 hp bogs down under load

he,s the one without a clue I appriciate your intelligence J thats why he,s here to get opinions and advice but i don,t have the motor here i,m simply stating (PROBABLE Causes for this happening not a fact no disrespect but any help is better than none at all. This site is blessed to have great minds like your,s here.

When's the last time you saw a dist cap on a V6 Mercury?

 

[j_martin]

Re: 1998 mercury 150 hp bogs down under load

Mine's rigged for 6100 rpm lightly loaded, runs 5900 - 6000 most of the time, and I carry a 2 inch steeper prop for when I have a heavy load, like hauling camping gear, a morbidly obese fishing partner, or pulling skiiers. It only takes about 3 minutes to swap props if needed.

 

[shankforce]

Re: 1998 mercury 150 hp bogs down under load

When livewells are full it takes forever to get on plane. Also when loading boat on trailor it stalls the motor completely out. Forgot to mention that it is on a Triton 18' bass boat. Sporadic idling when in gear. Any help please.

Well I am trying to answer the origial question. Sometime with these motors you have to think outside the box. Compresion then spark then fuel is a good starting point but not the answer to everything. Most of my problems with motors like these have not been any of the above issues. I have had a mercury tilt switch cause these issues or a intermitent stator cause these issues becouse each were electric componets on the way out. I would inspect this motor completely by eye before you do anything. I had a magnet come from the flywheel that clung to my trigger arm that cauesed bogging and stalling too. Or a water seperator that was full or had a hole in it causing problems.

 

[CharlieB]

Re: 1998 mercury 150 hp bogs down under load

How long since the carbs were cleaned?

AFTER you confirm compression and spark, think about how much fuel has been run thru the boat, AND how long it has been left sitting. Makes you wonder how some of these motors manage to still run at all.

 

[plumber1]

Re: 1998 mercury 150 hp bogs down under load

Mine's rigged for 6100 rpm lightly loaded, runs 5900 - 6000 most of the time, and I carry a 2 inch steeper prop for when I have a heavy load, like hauling camping gear, a morbidly obese fishing partner, or pulling skiiers. It only takes about 3 minutes to swap props if needed.

My motor runs at 5600 rpm wide open and it has a 25 pitch 4 blade prop from factory. It is slow on hole shot even with the 4 blade prop. The part that dont make sense to me is that at top end the boat and motor run great with no problems. Once it finally gets on plane it runs fine. It does have good compression, new plugs and as for fuel air mixture I have no idea.

 

[jeffersondodson561]

Re: 1998 mercury 150 hp bogs down under load

What is the serial number of this motor, carb/efi?

 

[jeffersondodson561]

Re: 1998 mercury 150 hp bogs down under load

=It is slow on hole shot even with the 4 blade prop.

You would get a faster hole shot with a 3 blade, not saying that is your problem but once you get it fixed, if you like to **** and git...a 1 blade prop would be the most efficient if not for the counter symetrical force.

 

[j_martin]

Re: 1998 mercury 150 hp bogs down under load

5600 WOT on a heavy boat would bog on the hole shot unless the prop is ventilated. Also, if the boat is gaining water weight, this would be the manifestation.