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


Capslock's Avatar
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06-03-09, 11:28 AM   #1  
Engine will not start now - loss of pwr, but it ran great for the last two weeks

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

 
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samuari's Avatar
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06-03-09, 05:46 PM   #2  
Great discription, it will help a lot!

It does sound like it's not running on all the cylinders, we just need to find out why.

First I would remove all the spark plugs and see if they are wet with fuel. I would bet some will be wetter or darker than others so take note wich cly they came out of #1 cyl will be the one at the top of the motor #2 will be on the oposite side next one down.

If you have darker ones take a cleaner one and see if there is spark on the cyl that is dark. Actually check spark on all 6 cyl.
If there are cyl. with no spark take note as to wich one or ones and let us know it could be a coil pack or a switch box.

If there is spark on all 6 remove the airbox and open the trottle plates all the way. look down the throughts and squeez the primer bulb and watch for fuel flowing into the carbs. The neadles should hold the fuel from overflowing into the throughts.

If fuel flows into the throughts get new carb kits and rebuild the carbs.

 
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06-03-09, 05:55 PM   #3  
This wouldn't cause this but the spark plugs should be hand tight + 1/4 turn with a wrench.

The motor shouldn't need to cool down after running at any speed.

I would change all the spark plugs after this, they are cheap for the price it's not worth cleaning and most times after cleaning they will accumulate carbon faster.

 
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06-04-09, 06:15 PM   #4  
So here is the update:

I was not able to do much with my time/skill set (lack there of).

I found two things:

A: I went to use the pump/fuel primer, it was firm. I tried to start the engine and it just did not even try to turn over. I took the hood off to look at the spark plugs and noticed the fuel filter was dead empty. Strange I thought, since the fuel pump was firm. I went to check the fuel primer again and its still firm. Tried to pump it lightly and slowly and that actually made he fuel go through easy and it filled up the fuel filter.

I tried to start the engine again, this time the engine did seem to try to start but still no go. So now i start to take the spark plugs out and I noticed one thing...

B: for visual perspective, imagine you are on the boat, looking at the "front" of the engine - the pistons/spark plugs would be found on the back side. The BOTTOM LEFT spark plug (number?) - i noticed, and i did not see this with the other spark plug holes, but there is a chance that i was not paying attention - smoke was coming out of that spark plug hole. It seemed to be a decent amount. The spark plug on this cyl. also looked a bit odd. I did not touch it to confirm, as to not to risk spoiling the spark plug with oil from my hands, but it appeared to be a bit...rough? It could have easily been residue on the plug though.


However, this smoke leads me to believe there is an issue.

Since this boat is in the water docked, and I have very little knowledge on engines, I decided that this might be the time to call in my boat doctor - which is coming to stop by on sat.

Does anything pop up in your head about this?

I intend to have him do a compression test. Is there anything else I should watch out for?

 
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06-04-09, 06:30 PM   #5  
It is difficult working on the motor when it is on the water, I've gone for a swim a couple times doing that.

The filter being empty isn't abnormal.

What does the "residue" look like? A little smoke is also normal, but if a piston starts to melt it will leave aluminum on the spark plug.

When you say it wouldn't turn over does that mean the starter wouldn't turn the flywheel?

A compression test and spark test will give you a good idea what is going on.

 
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06-05-09, 08:44 AM   #6  
well,

the spark looked like there was something other than oil on it.
this could have been aluminum, but it was not chunky - the spark plug looked more....scratched? then anything - but this could have also been caused maybe by the way the light hit the gas on the plug - causing it to look different - i dont think that is the case though.

the oil around the threads of the spark plug looked a bit excessive, but again I do not know.

when I said it didnt turn over, no the starter did turn the flywheel just fine. By turnover i meant the engine trying to take over from the starter and run itself.

I will have the boat doctor do a compression test and spark test - good thing to watch since I am not confident on the process to do such a thing.

 
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06-05-09, 08:47 PM   #7  
After watching how it's done you will be able to do it youself in the future, auto parts stores sell testers for under $50.

Keep us posted.

 
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06-07-09, 05:26 PM   #8  
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 like - 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.

 
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