Mercruiser bogging

[Renken89]

Re: Mercruiser bogging

Yea apparently the previous owner already ruined that for me its almost round. The hard fuel line is going to be on the purchase list along with the pump. While I'm at it how do I go about testing the fuel pump. I know it needs 5psi how do I go about the testing itself. Appreciate all the help thus far!

Well the bogging and shut off problem was fixed after the fuel pump clean up was completed. On to reveal a low WOT issue. The boat wants to run and will plane out on occasions. On too about 4k rpm. Going to recheck my previous work then move from there. Is their a chance an improper points gap could cause this issue? Or is that mainly do ignition because the boat starts and idols like a dream. Thanks fellas

 

[Renken89]

Re: Mercruiser bogging

After all this cleaning the fuel pump and replacing all filters the shut off and bogging has stopped completely. Only to be replaced with a low WOT. Fuel tank vent is clear, antisyphon valve removed cleaned, flows freely. Not sure how else to check it.. Do not see a pick up in my tank unless its built into the tank itself.. Questionable vacuum line replaced. Stumped from here. Words of wisdom welcome!!

 

[shotgundexter]

Re: Mercruiser bogging

I have been chasing similar issues with my 1999 3.0 mercruiser. I have replaced fuel tank, fuel pump, filters, fuel line, antisiphon valve. I am at the point of thinking mine is in the carburator. You are further along than I am, because Im still at the stage of it bogging when throttle is advanced.

 

[timfives]

Re: Mercruiser bogging

seems to be a common problem with these 3.0.. I just put a new carb (last year) and fuel pump this year. Mine Bogs down, and my top end is off. Once it is on plane it runs great and smooth.

So what i'm doing now, is the following.

1. Fuel I am gonna run a small tank and bypass my internal system to ensure venting / vacuum are all good ( i assume they are but hey you never know)

2. Timing. My bogging seems to come from the carb flooding, so it may be the timing is off not giving enough spark when it goes under a load.

3. I'm putting on a new coil.

I hope this helps a little, good luck and stay on it, i'm very curious how it works out!

T

 

[Renken89]

Re: Mercruiser bogging

seems to be a common problem with these 3.0.. I just put a new carb (last year) and fuel pump this year. Mine Bogs down, and my top end is off. Once it is on plane it runs great and smooth.

So what i'm doing now, is the following.

1. Fuel I am gonna run a small tank and bypass my internal system to ensure venting / vacuum are all good ( i assume they are but hey you never know)

2. Timing. My bogging seems to come from the carb flooding, so it may be the timing is off not giving enough spark when it goes under a load.

3. I'm putting on a new coil.

I hope this helps a little, good luck and stay on it, i'm very curious how it works out!

T

Found this stuff hanging out in my fuel lines. Ill be replacing the fuel tank as it looks like it has began to rust on the inside.

 

[NHGuy]

Re: Mercruiser bogging

You are almost there. Keep changing the filters and it will clear. I remember you said you emptied the tank and cleaned it. Is that true? If not run or pump it out of gas and then pull the sender and get out all the debris. As far as the low WOT, go through the checklist in the stickies at the beginning of the forum.
Of course also make sure it's properly tuned and adjusted, otherwise you are just trying to lipstick a pig!

 

[Renken89]

Re: Mercruiser bogging

You are almost there. Keep changing the filters and it will clear. I remember you said you emptied the tank and cleaned it. Is that true? If not run or pump it out of gas and then pull the sender and get out all the debris. As far as the low WOT, go through the checklist in the stickies at the beginning of the forum.
Of course also make sure it's properly tuned and adjusted, otherwise you are just trying to lipstick a pig!

I did clean the tank thoroughly the junk has arrived since the cleaning. Which leads to my assumption the tank is rusted. The pick up appears to have been welded into place at some point in time. From what I can see that even looks rusty. Did you see the picture? The sediments is what was in the fuel lines. What was in the pump itself was even heavier. It's a steel tank that came with the boat so I can't attest to age.

 

[NHGuy]

Re: Mercruiser bogging

I didn't re read the entire thread. If you have not changed the lines that's the last thing, unless you also do the tank. Changing the tank on some boats is hard and on others it's not. it's probably somewhere between a piece of cake and a PITA to change.
So could you take a look inside the tank? for rust? It would be visible probably. Especially if the fuel is removed. Is the tank in a spot where you could change it? Is your boat common enough that there are tanks the right shape available? I see Renkens on Winnipesaukee every time out. I bet M&M Marine Salvage in Meredith, NH has your tank. Only thing there is they charge 50% of new on everything. I can't bring myself to pay that much for the 25 year old bits I need unless they are the last place in the world.
I feel for you, got the boat almost done and whamo. You get hit with that.
Take a look in the Eastwood Company (car restoration) website. Maybe they have some solution.

 

[Renken89]

Re: Mercruiser bogging

I didn't re read the entire thread. If you have not changed the lines that's the last thing, unless you also do the tank. Changing the tank on some boats is hard and on others it's not. it's probably somewhere between a piece of cake and a PITA to change.
So could you take a look inside the tank? for rust? It would be visible probably. Especially if the fuel is removed. Is the tank in a spot where you could change it? Is your boat common enough that there are tanks the right shape available? I see Renkens on Winnipesaukee every time out. I bet M&M Marine Salvage in Meredith, NH has your tank. Only thing there is they charge 50% of new on everything. I can't bring myself to pay that much for the 25 year old bits I need unless they are the last place in the world.
I feel for you, got the boat almost done and whamo. You get hit with that.
Take a look in the Eastwood Company (car restoration) website. Maybe they have some solution.

The post of the fuel contents is just 3 or 4 posts back. The tank is easy it's above the deck..

 

[NHGuy]

Re: Mercruiser bogging

Yeah but did you replace the lines? And is the tank rusting out? If it's rusting you really do have to replace it. I'd also do the lines if you haven't. The rust is a safety issue to make sure there will be no fuel leak. The lines are to eliminate contaminants.