V150 won't plane...bogs down...kicks in...runs good...does it again...need help.

[1979Merc]

Let me start off by saying any help would be appreciated!

I have a 1979 Mercury V150 outboard. We have owned it since day one. It is only used about 3 times a year and over the last 5 years it has ran rough. It goes through maybe 2 tanks of fuel a year.

Here is what happens....it will struggle to plane out and seems to bog down. After running it a couple of miles it will kick in and run...then kick out....then kick it....and maybe run the rest of the day fine. The next day, it will start slow, struggle to plane out, seems to bog down, and may or may not kick in and run.

I have changed the plugs and plug wires. The gas in the tanks are now fresh. Still having same problems.

Could it be fuel pump? Power pack (not sure what power pack symptoms are)?

Any suggestions. I am fairly good with a wrench if I know which direction.

 

[j_martin]

Re: V150 won't plane...bogs down...kicks in...runs good...does it again...need help.

Don't run it that way. If it's a fuel problem, the lean burn will toast a piston or 2.

Have you changed the little fuel filter in the engine? Have you put in a fuel pump kit? Those are both maintenance items anyway, might as well try it.

If it still bogs, do the formal fuel system check out. You may have anything from gas/alcohos-water seperation to junk in the tank to a leaking suction line, yada yada yada.

If the boat is that old, and the gas tank is built in, it could be deteriorating and plugging up the fuel system.


hope it helps
John

 

[1979Merc]

Re: V150 won't plane...bogs down...kicks in...runs good...does it again...need help.

John,
That does help....thank you.

I have not put in a fuel pump kit yet....will this week. I have one ordered.

Where is the little fuel filter you speak of? Are you talking about the one inside the fuel pump housing?

We cleaned the tanks about 4 years ago, but I am sure they need it again. At that time, we replaced some of the fuel lines....we have had the primer bulb go limp a couple of times... if it sits for an hour or more. I may run new lines while I am at it.

Let me know about that filter... I am not aware of its location.

THanks.

 

[hkeiner]

Re: V150 won't plane...bogs down...kicks in...runs good...does it again...need help.

There are some troubleshooting tests you can do to confirm (or eliminate) some common fuel related causes of engine bog, such as a failing fuel pump, a restriction in the fuel line upstream of the fuel pump, or a vacuum leak in the fuel line. All you need is a vacuum gauge, a piece of clear hose, and a t-connector to do the troubleshooting. The below linked Mercury Service Advisory (#2001-17) provides pretty good guidance. Squeezing the fuel bulb during engine bog, to see what happens, may also provide some clues.

If the above mentioned fuel related tests do not indicate any problems, you might consider the ignition system (failing spark) as a cause.​

Good luck


http://www.marinepartsman.com/Mercury-Marine-service-bulletins/Mercury-Mariner/2001/EN_17.PDF

 

[j_martin]

Re: V150 won't plane...bogs down...kicks in...runs good...does it again...need help.

John,
That does help....thank you.

I have not put in a fuel pump kit yet....will this week. I have one ordered.

Where is the little fuel filter you speak of? Are you talking about the one inside the fuel pump housing?

We cleaned the tanks about 4 years ago, but I am sure they need it again. At that time, we replaced some of the fuel lines....we have had the primer bulb go limp a couple of times... if it sits for an hour or more. I may run new lines while I am at it.

Let me know about that filter... I am not aware of its location.

THanks.

On my XR4 there's a filter about the size of your thumb between the fuel pump and the carbs. It might not be there on your maching. I totally removed mine and put in a Racor 60gph fuel filter/water seperator instead.

Aftermarket fuel components, ie primer bulb and hose, don't have enough capacity to run a 150 properly. Use Genuine Mercury. This goes double for the bayonet fuel connector.

To see for sure it's a fuel problem, try this. there are 2 fuel connections on each carb. usually they are daisy chained together, leaving one connection with a plug in it. If they are manifolded together, there are 3 unused plugs. Replace any fuel fitting plug with a barb for a small hose to a 15 lb (10 will work) pressure gauge, and rig a line long enough so you can see the gauge while you're running. This is a temporary setup, as it is dangerous without a gauge isolator under the cowl. (a broken gauge line would spray fuel all over)

Normally they run a couple of lbs at idle, 5 or so at WOT. Anything above 2 is plenty. If it's a fuel problem, you'll see the gauge dive to 0 when the trouble manifests itself.

hope it helps
John

 

[1979Merc]

Re: V150 won't plane...bogs down...kicks in...runs good...does it again...need help.

Guys,

I found a new power pack/switch box at a local dealer for $75....I thought that was pretty good since they seem to be $150 everywhere else. WOuld it be worth changing considering it is a 1979 motor......
Fuel pump kit to be here in a few days also....

What are the symptoms of a bad power pack/switch box? I just have this feeling my problem may be electrical.....who knows?

Give me your opinion on the power pack/switch box replacement....I figure for $75, that is not too bad.

Thanks.

 

[j_martin]

Re: V150 won't plane...bogs down...kicks in...runs good...does it again...need help.

If yer made of money, just go buy a new motor.

Seriously, you can throw a lot of money at it, and there's only one or 2 things that actually are bad. Also, putting used parts in when you don't pay attention to the diagnostics will likely introduce yet another layer of malfunction, which will make it real fun (and expensive) when it finally gets to the mechanic.

Do what the guys here say. We're trying to help, banking on probably centuries of experience (collectively), using the thin amount of observed data that you give us. Do what we say, say what you see, and you'll be surprized how quick you can get to the answer.

hope it helps
John

 

[1979Merc]

Re: V150 won't plane...bogs down...kicks in...runs good...does it again...need help.

John,
No one is second guessing you guys. I appreciate your experience and plan on trying the advice.

I was just inquisitive as to whether the power pack could be the culprit as it "acts" electrical as my experience has been with older vehicles.

The $75 power pack is a NEW part. Therefore I should only be eliminating problems.

Not made of money. Greatly appreciate the advice.

Will a V150 6 cylinder run on 3, 4, or 5 cylinders?

Thanks in advance.

 

[hkeiner]

Re: V150 won't plane...bogs down...kicks in...runs good...does it again...need help.

I was just inquisitive as to whether the power pack could be the culprit as it "acts" electrical as my experience has been with older vehicles.

Yes, a bad power pack can cause the type of problems you are experiencing. The thing is, so can a quite a few other failed electrical components and/or failed fuel system components. That is why systematic troubleshooting is often the suggested appoach. A vacuum gauge (for testing your fuel system) and a DVA meter and multimeter (for testing your electical system) are pretty much the tools you need to do an effective job.

In addition, I personally like using a SmarTach meter to check secondary voltage levels when a motor is experiencing bogging symptoms at high speed. It is relatively easy to move it's sensor between the spark plug wires while the motor is running at high speed. Alternatively, an induction type timing light can be used to detect complete voltage failure in the spark plug wire, but is not as effective for detecting weak voltages.

 

[1979Merc]

Re: V150 won't plane...bogs down...kicks in...runs good...does it again...need help.

Found a few interesting things....

The primer bulb and hose from the tank selector switch was 1/4" or maybe 5/16" at best. I replaced with 3/8" hose and Mercury bulb. I know we have replaced this in the past and may have made a mistake there....not sure if 1/4" or 5/16" would cause the problems versus 3/8".

I rebuilt the fuel pump. One small gasket inside the bowl of the diaphrams was deteriorated.

Ran new 1/4" lines from the fuel pump to each carb.

Found two old wires that the insulation was cracking off from the stator to the switch box....I shrunk heat wrap and eliminated that potential problem.

Taking it out Saturday morning.

 

[j_martin]

Re: V150 won't plane...bogs down...kicks in...runs good...does it again...need help.

Found a few interesting things....

The primer bulb and hose from the tank selector switch was 1/4" or maybe 5/16" at best. I replaced with 3/8" hose and Mercury bulb. I know we have replaced this in the past and may have made a mistake there....not sure if 1/4" or 5/16" would cause the problems versus 3/8".

You got that one right!

John

 

[CharlieB]

Re: V150 won't plane...bogs down...kicks in...runs good...does it again...need help.

Your ignition system is actually TWO systems piggybacked each one operating 3 cylinders both sharing the stator and triggers. They can go bad intermittantly before dying completely. Testing is required to determine which component is failing.

75 for a 200+ module is a very good deal, if you can afford to keep it on a shelf until you need it.

A DVA meter and the CDI Ignition Troubleshooting Guide is THE resource for determining ignition problems.

In a perfect world it is recommended to change those ignition modules in pairs IF that is the problem, in the real world we end up changing only that expensive part absolutely required to restore motor performance.

 

[hkeiner]

Re: V150 won't plane...bogs down...kicks in...runs good...does it again...need help.

Here is what happens....it will struggle to plane out and seems to bog down. After running it a couple of miles it will kick in and run...then kick out....then kick it....and maybe run the rest of the day fine. The next day, it will start slow, struggle to plane out, seems to bog down, and may or may not kick in and run.

Since your symptons are intermittant, I would guess (and it is a guess) that the problem is an ignition failure rather than a fuel supply failure. In my experience, a fuel supply restriction tends to cause a more constant bogging symptom. But anything is possible.

If I had your sysmptoms, testing the voltage (spark) during engine bog would be one of my first troubleshooting steps.

 

[1979Merc]

Re: V150 won't plane...bogs down...kicks in...runs good...does it again...need help.

hkeiner,
I would agree with you regarding it being an ignition failure. Though I have now rebuilt the fuel pump and also found an undersized fuel line/primer bulb.
Will run tomorrow to see if improvements were made.

Before the last outing, I replaced the plug wires and new plugs....did not help.

If you could feel it kick in and out you may agree with the spark/ignition failure theory....it is instantaneous when it goes from bad to good or back to bad. Just like something not firing.

Thanks for all of your help. I will give an update tomorrow (Sat.) afternoon.

Meanwhile, if you have any more on water tests, please send them out today...I am desperate. This is the only problem I have with my rig (1-owner 1979 Ranger V150 garage kept from day one with many upgrades) before it hits the market ($3000) to be replaced with a new Ranger 188VS 175 Mercury Pro XS soon....I know...that was a cheap shot description.

Thanks.

 

[hkeiner]

Re: V150 won't plane...bogs down...kicks in...runs good...does it again...need help.

Meanwhile, if you have any more on water tests, please send them out today...I

Once you know the results of your troubleshooting tests of the fuel and igntion systems (as described previously in this thread), the next steps will be more apparent or at least narrowed down.

 

[1979Merc]

Re: V150 won't plane...bogs down...kicks in...runs good...does it again...need help.

UPDATE....
since initial post...fuel pump rebuild (though it did not have the 2 little check valves in the kit--just gaskets and diaphram), new fuel lines and bulb.

Ran today....same symptoms....bogs down-will not plane out (20% power) and I stand on the bow and it picks up and run ok, but not up to par.(50% power)...then it would kick in and run great for about 2 minutes (100% power)....then kick out (70%), then kick in for 5 seconds (100%) and then out (50%-70%)....never ran perfect again. It would plane out by itself at about 70% power.


All cylinders spark across a spark indicator light....does not tell alot

Pump the bulb while running....does not change things (actually seems to drown the engine down some)

*Interesting....the little vacuum tube-like tube running from a small fitting off the #2 cylinder housing around to the manifold will blow off and split...I will cut off end and later when it sputters/spits again at idle, it will blow off again....no other cylinders will do that. Seems to run the same with it on or off.

Just seems like a spark thing to me....seems to be getting gas...or maybe carb...who knows. I just want it to run like it does when it is 100% which is extremely intermittent.

Is it a failing switchbox/powerpack? Seems like the 100% good times are getting fewer and fewer.

 

[hkeiner]

Re: V150 won't plane...bogs down...kicks in...runs good...does it again...need help.

Is it a failing switchbox/powerpack?

Knowing the results of your troubleshooting tests of the fuel system (following the Mercury Service Advisory) and your tests of the ignition system (using a DVA meter and multimeter) while the engine is bogging, I might be able to give you a good opinion on the probable cause. Otherwise I would only be guessing the same as you. Others on this site, with more experience, may be better able to diagose the cause considering only the way the motor runs. Sorry.

 

[Ed R]

Re: V150 won't plane...bogs down...kicks in...runs good...does it again...need help.

Hey, the sator under flywheel has 2 sets of windings, blue, for low speed, and red for high speed, for 135,and 246cylinders! You would know if they were not working. sounds like you have dirt or debre in high speed nozzles in carbs old fuel varnish, etc....

 

[Ed R]

Re: V150 won't plane...bogs down...kicks in...runs good...does it again...need help.

also, pick up timing between roller cam on that 2 lilter model 122cc was very important [for that out of the hole shot] . E.R.P.

 

[bagnallt]

Re: V150 won't plane...bogs down...kicks in...runs good...does it again...need help.

hi my 2cents worth .

I have the same problem .. I have a 50 johnson 1973..... when you hit the power it takes for ever to get up there boging down then when it reaches a certain revs it speeds up and finally planes out.
So I rebuilt the carbs fitted new fuel pump . new coils stater check out everything you could think of.. Compression checks spark checks..
I was about to use the motor as an anchor..
Then one evening i was tinkering and i saw the problem.... I have arcing from the top cylider spark plug boot straight to the engine block. so intermitant power to top cylinder.... may be worth a look for you ... too