1998 Mercury Outboard 150 MIDRANGE ISSUE - Watch VIDEO , PLZ Help!!!

[Ant-Knee]

Hello All,,

This is the problem I am having.. The boat Idles Fine and tops out fine and runs at 45 Mph...

If I throttle up fast the boat will take off, If I throttle up slow she starts to bogs at 1800rpms every time and if I don't ease off or throttle through it she will DIE!!!

I have switch power packs - No Change
Rebuilt carbs twice - No Change
Tried Different set of carbs - No change
Rebuilt Fuel Pump - No change
Ran on external fuel Tank- No Change
New Plugs - No change
New Wires - No Change

 

[Chris1956]

How does it work under load? Revving in neutral proves nothing.

You addressed all the usual suspects. I am not sure what to suggest. The poppit valve becomes active at about that point, and the stator switches to the high-speed winding at about that point. I don't see what the poppit valve would do. Maybe something in the transition between low and high speed windings in the stator? Just a guess.

Can you live with revving her up fast? Most people only do that......

 

[enginepower]

Chris, he IS under load as he is in gear probably on trailer. Sounds like it's flooding or starving for fuel but seems you attacked that already. Does it run great at WOT for a long time with no bogging or missing? It's slowly losing power like a fuel issue tho. I doubt this is it but did you do a linkage resynch? Have you tried hitting your choke to enrich the fuel and see if that changes anything? Or even disconnect richen line to see if maybe it's sucking fuel past it. (I think if you get the lines swapped it can do that)

 

[Teamster]

I had a kicker that did something like that, It was an exhaust leak,.....But you have the hood off so I doubt that's it,....

 

[Ant-Knee]

Chris, he IS under load as he is in gear probably on trailer. Sounds like it's flooding or starving for fuel but seems you attacked that already. Does it run great at WOT for a long time with no bogging or missing? It's slowly losing power like a fuel issue tho. I doubt this is it but did you do a linkage resynch? Have you tried hitting your choke to enrich the fuel and see if that changes anything? Or even disconnect richen line to see if maybe it's sucking fuel past it. (I think if you get the lines swapped it can do that)

Correct, Boat is strapped to my trailer and under load in gear, I thought it was in the fuel system as well but I just cant find anything wrong there,
It is getting plenty of fuel.. I am waiting on new gasket kits for carbs once again... I know its not in the carbs tho.. I have been through them twice and doing them one more time but that's it...

I did the linkage / resynch couple times, still no luck..
I tried the choke thing and tried to squeeze primer bulb, no change..
I also disconnected the idle stabilizer - No Change

My thoughts are now in the ignition, stater or trigger... Since I switch power packs that should eliminate them as the culprit...
I am thinking maybe the stater has a bad/weak spot or something... Is this possible? What I don't understand is if the stater was weak or bad would it make the boat run like crap totally instead of just 1800 rpm.? I can run at 40 -45 mph all day long at 5500 RPM... Idles perfect and top end is awesome, only problem is when it hits 1800rpm, I either throttle through it or it bogs and dies.... I am really boggled with this... If I had a spare stater that would help but at 500.00 a pop I hate to swap it and found out that's not it..., That's allot of money and I am not rich..

Thanks guys

 

[Ant-Knee]

I had a kicker that did something like that, It was an exhaust leak,.....But you have the hood off so I doubt that's it,....

Did not try this....
How do I check for this issue you mention???

Thanks for your help!!!

 

[Ant-Knee]

How does it work under load? Revving in neutral proves nothing.

You addressed all the usual suspects. I am not sure what to suggest. The poppit valve becomes active at about that point, and the stator switches to the high-speed winding at about that point. I don't see what the poppit valve would do. Maybe something in the transition between low and high speed windings in the stator? Just a guess.

Can you live with revving her up fast? Most people only do that......

Chris I am under load in video, In gear strapped to trailer at the boat ramp..
The motor runs perfect in neutral and in driveway, You would never know it had an issue till you go in gear and hit 1800 rpm.

Well I did the poppet valve as I do this on a yearly schedule with water pump and it was just done at the beginning of the summer, No over heat issues at all...
I don't mind revving her up that's what I have to do as of right now, Its either all or nothing...
But I troll allot when I fish and it is a pain in the ***** come trolling time..


Thanks for your info..

 

[Ant-Knee]

I am suppose to bring it to Anglers marina on Wednesday and drop it off there, but I am not to crazy about letting them work on my boat, I have fixed my car and boat myself and have not been to a mechanic in several years... I would rather do this myself but I am bogged down with this one... It has been driving me nuts to find the problem here...

 

[Teamster]

Did not try this....
How do I check for this issue you mention???

Thanks for your help!!!

On my kicker it would idle or run wide open,....But the exhaust leak would choke it out at trolling speeds,.....So I took the hood of for trolling,..

But, Being as you have the hood odd in your video you should be clear of that,.....

 

[enginepower]

Does it start back up easily or it has to spin a while before restart? It actually sounds like it is flooding. Did you try removing the line from enrich solenoid to see if any change?

 

[Ant-Knee]

Does it start back up easily or it has to spin a while before restart? It actually sounds like it is flooding. Did you try removing the line from enrich solenoid to see if any change?

Yes, Starts back up fine, Normally just one touch of the key...
Yes, I did remove the richner , No change...

I agree with it sounding like a fuel issue, I have been auto mechanic for long time just new with the outboards..
Maybe something got caught up in the bowl of the middle carb and the valve seat is not cutting off the fuel supply...
The carb kits I ordered will be here today so I will have this other set of carbs rebuilt and back on tomorrow... I have soaked 2 of the 3 carbs 3rd is
soaking now and will be ready to be blowed out tonight...

Please guys, Keep the suggestions coming...


Thanks for your help guys...
Much appreciated...

 

[Ant-Knee]

I am thinking this would be an issue with the center carb since it is a mid range problem, Would this be correct?
Thanks,

 

[flyingscott]

No that is not correct at all. I would check your float level it sounds like it is running rich or something happened to the timing. The reason i say rich is because when you punch it you give it enough air to burn the excess fuel off. Like pushing the gas pedal down to start a car after its flooded. Also it kinda sounds like a diesel when you accelerate until it gets cleared out. Or you have a bad lync and sync. I think you have an issue with the idle circuit or or low speed timing. You need to check 3 things the lync and sync,the stator and the float levels.

 

[Ant-Knee]

Ok, carb Kits came in mail, I am putting carbs back together now... The reason I don't think it is in the fuel or carbs, I rebuilt the carbs twice.. Squeaky clean.. checked floats, All looked good... I have an extra set of carbs that were in need of rebuilding, I threw them on without cleaning them just as a test and it did the same exact thing...

But I will clean them and put them back on and do the sync/Link.. I am not sure on how to test the stater, Can you please advise?? I do have a DVA Adapter if needed for this..


Thanks al,

Ant......

 

[Ant-Knee]

Heres the last carb broken down...

 

[Ant-Knee]

Well I think I may have found the problem, Not sure but maybe..

The little jets on the front of the carbs that were on the boat were pretty clogged up, not all of them but I think 3 out of the 6.. The big jets were ok..
I have not gotten into the carbs to see what is in the bowls yet but I think this crap is coming from the fuel lines, I run my hand down the line and my hand is now black..
That should not happen, I wonder if the fuel lines are causing my problem.. I will know more when I open the bowls from the carbs that were on the boat.. I will replace all the fuel lines and fuel filter under the cowling before I putt on my clean carbs on..

I would like to ad another fuel filter, maybe right before the fuel pump, Is this ok to do? Ill put one before and one right after just before the carbs...
Ill go get fuel line tomorrow after work...

I hope this does it for this issue...


Thanks,

Ant..

 

[Chris1956]

Install a single water separator in the boat. That will filter and remove any water from the fuel. They have 40GPH capacities, so the motor will not starve for fuel. The inline filters are not nearly as good.

Obviously you need to find the source of the dirt in the fuel line, or you will not have success. You still have an odd issue though.......

 

[Ant-Knee]

I am hoping the crap in the carbs is coming from old fuel lines,
I am not confident that this is going to take care of it tho.
I do run a water separater on the boat but I by passed this as one of my test and it had no change..

I have been dealing with this issue for sometime now and it did the same thing right after each carb clean / rebuild..
I cant see the lines clogging carbs immediately after cleaning... But I am hoping that I am wrong... I am kind of stuck now till my lines get here..
I ordered all new bleed lines, Fuel Lines, and a couple Fuel Filters... I will also put new water seperater filter..

I will post back shortly,

Thanks again all,

Ant....

 

[hunter200524]

First off i dont recommend putting the motor under load without the airbox on. thats a no no. One way to tell if you have a fuel issue is when you are having the problem spray carb clean into the intake, if it picks up then its fuel if it doesnt change or boggs than its something else. Thats a good place to start. What size of boat is this 40mph seems a little slow. There is a chance that you have some scored cylinders.

 

[Ant-Knee]

Well boat actually does 45 at 5000 rpm, If I swap props Ill get 5500rpm out of it...
With the other prop I think I got 5500 at 48-49mph.. But I rarely move the boat that fast...
I fish with a few older gentleman and they like a slow ride, But that's ok with me.. I don't mind..
I thought the air box was just a silencer, Didn't think it could hurt running without it...Thanks for the heads up on that...
I don't have a leak down tester, But I will try and get one.. We did a compression check and all the numbers were really good across the board..
I will do a compression check again and see what numbers are again..


Thanks,

Ant...