Engine will not start now - loss of pwr, but it ran great for the last two weeks

[capslock118]

Hi there,

I will be as detailed as possible so I will try to be short:

Engine: 2-stroke 135hp outboard mercury.

Launched the boat two weeks ago, ran beautifully. Went on the boat last weekend, ran terrific.

Yesterday, went to start up the engine - turned over, ran ok. I let it warm up at a little more than 1k rpm. About 1 minuite into warming up, the engine stalls.

I go to try to kick it back in, it turns on, then about a second or two later turns off. I then have the throttle open all the way to try to get it to kick in, it turns on - revs up extremely high because i was slow to turn it down, i turn it down immediately - then i keep it above 2k to 3k rpm...then, it starts to lose power - in this time I am trying to push the throttle all the way to try to give it more gas, power still tanks and the engine stalls.

I continue to try to start the engine up, no luck. I find that my battery is completley dead - try a new battery. The engine kicks in when it is on idle with no choke - however only lasts for a few seconds and sometimes I hear knocking (i think). A neighbors opinion at the harbor was that it was flooded and only half the cyclinders are firing.

Today:
new battery, try to turn the engine over - does not start. There is some indication it is trying but no go.

Few things to note:
I thought this was strange, but my manual said to tighten the spark plugs by hand, with no wrenches - they still seem tight, but do you suppose this is a problem?
Once the battery appeared to be very dead, barely turning the engine, the buzzer started going off (and the RPM meter was given very false readings) - is this a sign of a larger problem?

Is it possible that when it was running fine, i turned off the engine too soon before letting it idle, where by clogging the spark plugs? (they are brand new as of apr 2009)

Should I change my spark plugs again? (ps. they are the type without the lip on the top - per manufacturer)

Why would only half the cylinders be firing and my assume hearing of knocking?

I ask these questions because this is all of a sudden.

Let's figure out what the cause is here. we know its not the battery anymore, because i replaced that with a new battery of equal size

 

[Chris1956]

Re: Engine will not start now - loss of pwr, but it ran great for the last two weeks

Remove the plugs, note their color and condition and install them finger tight. Now tighten them with a wrench.

I would inspect the fuel for water or suspended alcohol/water mix.

Take a compression test and test for spark on all cylinders. post back the results and the year of the motor.

 

[capslock118]

Re: Engine will not start now - loss of pwr, but it ran great for the last two weeks

Hi chris, thanks for the response.

To note a few things:

the fuel tank is permanent and sealed underneath the boat. All i can see when looking at the tank is the electric wire for the fuel gauge- how should i check then for fuel/water mix?

The engine is from 1990 (well, the boat is, and it came with the boat when it was new).

Compression test - i have been avoiding this since the beginning of the year, is this procedure difficult when the boat is docked in the water? also - would I need to worry about the water impeller / cooling when doing this test i.e. can i have the engine in 'trailer' position in order to do this test? it would be the easiest in order for the tester and my hands to reach the cylinders in this way.

 

[sschefer]

Re: Engine will not start now - loss of pwr, but it ran great for the last two weeks

Sounds simple as a plugged fuel filter to me. Did you check it yet? If not just change it and see what happens. It's a really cheap fix if that's all it is.

 

[capslock118]

Re: Engine will not start now - loss of pwr, but it ran great for the last two weeks

sschefer,

I did take a look at the fuel filter - mine is the small white in-line type.

It looks fine to me (as if i really know), the liquid inside is that typical color of gas.

It was also replaced this year before putting the boat in the water - would it have become damaged within that time for some reason?



I also suppose it is worth mentioning that when it was on for the brief time that it was, after the first stall, the exhaust had a hint of blue. I believe that indicates an oil-rich burn. Would this indicate anything outside of the mixture not being nominal?

 

[CharlieB]

Re: Engine will not start now - loss of pwr, but it ran great for the last two weeks

A little blue smoke may just be from unburned oil, one or more cyl's not firing for any of a number of reasons.
(My spelling really sucks tonight, three, now four, red lines in the first sentence, hate to see my posts without a spell checker built in)
Moisture WILL accumulate in a fuel tank, roll down and hide under the fuel until it builds up deep enough to sucked up by the fuel pickup tube, then it gets into the carbs and causes problems.

Pull the fuel line off the engine, stick the pointy end of a zip tie into the hose fitting and pump a small sample into a clear container, let it set 5 minutes and look at it. Does it have any beads rolling around in the bottom under the gas?

If so, then you have your problem. Weight the craft such that the tank sender is on the low side, let is sit long enough for all the water to collect in that corner of the tank. Hopefully the tank isn't so full of fuel that you can't remove the sender without leaking fuel into the boat. If so, pump fuel out into gas cans until it is safe to remove the sender.

Stick a hose down into that bottom corner of the tank and pump out the water until you get clean fuel.

Now, install a water separating filter to prevent any further future contamination of the engine.

Drain each carb float bowl, one at a time, pump the primer once or twice on each bowl to flush clean from your now clean fuel supply.

Add water (muffs or float your boat) and stir.

 

[sschefer]

Re: Engine will not start now - loss of pwr, but it ran great for the last two weeks

Good advice Charlie. The only thing I would suggest it that before you suspect the worst, verify it by buying a 3 gal fuel tank and using it to test with. If the problem clears up then you know its in the main fuel tank.

If it doesn't clear up then you know that you have a problem at the engine and can begin to perform the basic trouble shooting steps.

 

[CharlieB]

Re: Engine will not start now - loss of pwr, but it ran great for the last two weeks

I agree that the test tank is a great idea, however, if water is already in the carbs it may be too late and clean fuel won't run any better with the water already in the carbs.

Taking a sample at the fuel connector and if it is good, then testing with the test tank would give him the best of both approaches.

We should get together more often, I bet we could solve many problems in record time.

 

[sschefer]

Re: Engine will not start now - loss of pwr, but it ran great for the last two weeks

I agree that the test tank is a great idea, however, if water is already in the carbs it may be too late and clean fuel won't run any better with the water already in the carbs.

Taking a sample at the fuel connector and if it is good, then testing with the test tank would give him the best of both approaches.

We should get together more often, I bet we could solve many problems in record time.

Agree, if he removes the bowl plug from each bowl and drains them this will remove the water but catching a sample there would be difficult. You're right best to get sample from the tee at the loop on the main line.

 

[capslock118]

Re: Engine will not start now - loss of pwr, but it ran great for the last two weeks

so the boat doctor came out on sat morning.

it is a bit silly but it was an extremely simple problem, but i would not have identified it myself until now.

It turned out just to be the fuel line - particularly the pumper you press to push gas through the line.

The reason it was so firm while the fuel filter was empty was that one of the valves in the primer was jammed. He just shook it, knocked it around a few times. We took the line off the engine and forced the valve open to release gas. After that it was smooth sailing.

It was good that he came out though because the engine was running at a low RPM at idle so he did a little monkey-ing around to tune it up and now it starts in a flash.

I still need to get a new fuel line to replace the old one, but I was able to fully enjoy the boat this weekend. Kind of a kick in the arse since I intended to replace that line before I put it in the water but was too lazy to do so.

Anyways, totally worth the $25 he charged me for his time to tell me this was not going to be a $1,000 project as I had feared (for the worse).

HOWEVER - He did do some tests on the electrical and pointed out that the stater (correctly spelled?) is going. But he said there was no telling when, if at all, it would go while the boat is under my ownership. I will see how that goes down the line since there is no guarantee on when it will go.

 

[sschefer]

Re: Engine will not start now - loss of pwr, but it ran great for the last two weeks

Good news!. I had mine out running sweet this weekend also. It's a good feeling. As for the stator. I wouldn't get too worried about it. If you start noticing a gradual loss of power or suddenly run into a no spark condition then at least you know the most likely suspect.