Engine hesitation

Sparky · Post by **Sparky** » Sun May 18, 2008 1:21 pm

I recall this issue being discussed on another thread. While on my ride to Trois Rivieres, my Kermit (Metro 125) suffered a power loss at around 1/4 of a tank left. The first incidence was after a truck passed me in a curve, leading me to think either my hand slipped on the throttle or turbulence disturbed airflow into the engine intake. It died twice, both before and (very luckily!) right after I got off a high-speed bridge over the St. Lawrence. The first time it revived with electric start, the second with a kickstart.

The symptoms recurred on a ride home after a second fill-up. To avoid a full engine die out, I would drift to the side of the road and chop throttle. After a few seconds, the engine would go back to full power. This happened a few times within the space of a half hour, again in the same range on the fuel gauge.

Oil and spark seem to be alright. I checked all fittings for the transmission oil and the engine oil level. Spark seems to be okay, although I haven't really checked the spark plug. The problem seems to be--to my minimally-mechanical eyes--a ghostly gremlin in the fuel/air delivery. Something around 1/4 to E causes a disruption to either the carb or cylinder when on high speed runs.

Is Kermit complaining about an overheating engine? Is this the four stroke equivalent of a soft seize? Or is this a transient problem that will go away?

brimstone · Post by **brimstone** » Sun May 18, 2008 1:28 pm

can you get vapor lock with a 1/4 tank? maybe some loose wire somewhere.

MarsR · Post by **MarsR** » Sun May 18, 2008 2:04 pm

Any chance of some kind of fuel contamination (water condensation, dirt, sunscreen, whatever)?

brimstone · Post by **brimstone** » Sun May 18, 2008 2:07 pm

MarsR wrote:Any chance of some kind of fuel contamination (water condensation, dirt, sunscreen, whatever)?

sunscreen? now that's random. hehehe

MarsR · Post by **MarsR** » Sun May 18, 2008 2:32 pm

brimstone wrote:
MarsR wrote:Any chance of some kind of fuel contamination (water condensation, dirt, sunscreen, whatever)?
sunscreen? now that's random. hehehe

I thought it more likely than, say, lollipops.

louie · Post by **louie** » Sun May 18, 2008 2:48 pm

this one?

viewtopic.php?t=3428&highlight=

Sparky · Post by **Sparky** » Sun May 18, 2008 2:53 pm

Fuel contamination...hmmm. Actually, yes. A long while back, when I did my first refill, there was some overflow. I grabbed a squeege to rinse off the area around the gas cap. Without putting the cap back on. Some of the window washing fluid got into the tank. It might be that the stuff finally got down to the carb, since I keep on refilling at 4 litres.

brimstone · Post by **brimstone** » Sun May 18, 2008 2:56 pm

with a liquid though, i'd think it would have mixed/diluted with your gas. and not really been a factor, but stranger things have happened.

jfrost2 · Post by **jfrost2** » Sun May 18, 2008 3:06 pm

This is quite common, if you have bad gas it will shut off or lose power until the impurity is burnt. Your full tank right now may be bad, try buying gas somewhere else next time.

MarsR · Post by **MarsR** » Sun May 18, 2008 3:26 pm

brimstone wrote:with a liquid though, i'd think it would have mixed/diluted with your gas. and not really been a factor, but stranger things have happened.

Not necessarily. You know how oil and water don’t mix. Well I’m not sure about gas and window washing fluid, but that could be a problem. Even just a little could stall the engine.

brimstone · Post by **brimstone** » Sun May 18, 2008 3:43 pm

it's possible i guess, but with them being so close it's hard to tell. what you could do is go get a gallon of gas, drain what you have out completely and fill it up from your jerry can.

toddrw2251 · Post by **toddrw2251** » Sun May 18, 2008 4:01 pm

Fill up the tank and mix in some seafoam. It dry's up water in the fuel system.