engine wont start - Tilted Forum Project Discussion Community

RoketaMan · 06-29-2009, 04:16 PM

I was wondering if anyone could help me..I have a 4 stroke 150cc scooter and for some reason it wont start up. The engine cranks but it just wont start. Some background info, I've had problems with the engine trying to start up and it wouldnt idle, it would just die. I had poor power and performance on it (it was accelerating slow and going 10mph slower). Can anyone please help??

shakran · 06-29-2009, 04:32 PM

if an engine cranks but won't start, you either aren't getting fuel, or you aren't getting spark.

First, remove a sparkplug, hook it up to the plugwire again, and crank. If you don't see a spark, remove the plug wire and hold it against a metal bolt on the engine while cranking. Look for the spark. If you don't see it, you have an electrical problem. Start with the distributor, coil, and ignitor. If you do see a spark, but didn't when you had it hooked up to the plug, replace the plug, and make sure it's gapped properly for your engine.

Assuming you have spark, take off a fuel line and crank the engine (obviously do not smoke, or have any open flame or hot items in the area when you do this, and do it outside so you don't burn down the garage.) If you don't see fuel spurting out, then you have a fuel delivery issue. Probably either the filter is clogged, or the pump is bad. Take off the fuel line before the filter to see if fuel is getting that far. Keep working backwards until you get to the pump to find the source of your fuel stoppage.

Another possibility is that the timing is radically off, which would mean the spark is happening, but not when the fuel/air mixture is right for combustion. Try adjusting the timing backwards and forwards while cranking to see if you can get it started, and if you can, then time the engine properly with a timing light (available cheap at auto parts stores, and I believe NAPA and Advanced Auto will lend one to you.)

RoketaMan · 06-30-2009, 05:13 AM

thank you so much!

Flinx · 07-02-2009, 05:51 AM

Quote:

Originally Posted by shakran

if an engine cranks but won't start, you either aren't getting fuel, or you aren't getting spark.

First, remove a sparkplug, hook it up to the plugwire again, and crank. If you don't see a spark, remove the plug wire and hold it against a metal bolt on the engine while cranking. Look for the spark. If you don't see it, you have an electrical problem. Start with the distributor, coil, and ignitor. If you do see a spark, but didn't when you had it hooked up to the plug, replace the plug, and make sure it's gapped properly for your engine.

Assuming you have spark, take off a fuel line and crank the engine (obviously do not smoke, or have any open flame or hot items in the area when you do this, and do it outside so you don't burn down the garage.) If you don't see fuel spurting out, then you have a fuel delivery issue. Probably either the filter is clogged, or the pump is bad. Take off the fuel line before the filter to see if fuel is getting that far. Keep working backwards until you get to the pump to find the source of your fuel stoppage.

Another possibility is that the timing is radically off, which would mean the spark is happening, but not when the fuel/air mixture is right for combustion. Try adjusting the timing backwards and forwards while cranking to see if you can get it started, and if you can, then time the engine properly with a timing light (available cheap at auto parts stores, and I believe NAPA and Advanced Auto will lend one to you.)

Don't think many scooters that size have fuel pumps, all that I've seen are gravity fed.
From personal experience I'd start with the air filter then goto electrical. After that I'd check to see if there was any fuel making it to the carburetor(s) by removing the drain plug thats usually at the bottom of the carb bowl, make sure you have something to catch the fuel if any comes out an look that gas color. Water in the gas can settle in the bowls and cause these problems.
Does it stream out or dribble? Stream is good, dribble is bad. Dribble means a fuel blockage somewhere, start with fuel filter then lines. If the filter looks clean an the lines seem clear of junk then this is where the fun starts, time to rebuild your carburetor(s), or if you feel lucky dump a bunch of cleaner into your tank, crank the engine for a bit to allow the cleaner to get fully into the system an wait a day or so to let it do it's thing.
If the the fuel streams out of the bowl drain plug then you probably have fuel and spark but maybe not compression. This is when it's time to get someone with the right tools and knowledge involved.

RoketaMan · 07-11-2009, 05:01 PM

Thank you so much!

1. I had an electrical problem and so I fixed it by replacing it with a new CDI box and a spark coil.

2. The scooter started up and drove fine for 25 miles. But now, it has problems starting up again. Prior to this though, my scooter would not idle (I would have to pull the throttle to keep it at a constant RPM). If I let go of the gas it would die. I've tried adjusting the idle on the carb but that didn't hlp.

I'm thinking it could be the carburator? Is there anything else it can possibly be? Would buying a new carburator and replacing it fix it?

Any help is seriously appreciated!

Thanks!

Bear Cub · 07-11-2009, 05:04 PM

What's the plug look like when you pull it?

Flinx · 07-12-2009, 04:44 AM

I wouldn't buy a new carb for it. They are fairly easy to strip down an rebuild and thats MUCH cheaper.

RoketaMan · 07-13-2009, 06:27 AM

I get spark, it just doesn't wanna start up. I think something is wrong with the carb or something with fuel. If it is not the carb, what else could it be?

shakran · 07-13-2009, 07:38 AM

I think Bear was more going for the color of the spark plug. Is there any discoloration on the white part?

Rediagnose from the start. Just because something wasn't broken when you checked it the first time, doesn't mean it didn't decide to die during the 25 mile drive. Make sure fuel is getting to the carb before you start stripping the carb down.

RoketaMan · 07-21-2009, 11:46 AM

Alright Thanks..I put a brand new spark plug in and it gets spark. Once I start stripping down the carb, is there something I'm something I'm supposed to look for or clean?

Thanks a lot for all the help!

telekinetic · 07-21-2009, 11:50 AM

What color are the sparkplugs?

Flinx · 07-22-2009, 06:52 AM

BUMP for the color of the plug, sooty black? Flaky white? Oily? The way a plug looks can tell you a lot of whats going on.
As for the carbs, see my previous post about them. Oh I can't believe I forgot to mention one other thing. between the carbs and the cylinder there is a rubber piece, check that for cracks/leaks.
My old 750 Seca RL had a startup problem for a bit till I discovered one of those rubber pieces had many cracks in it. Bit vague but I'm tired an burnt out right now

RoketaMan · 07-30-2009, 04:59 PM

Alright, the spark plug is black when I pulled it out. The rubber piece is in tact between the carb and the cylinder. I don't know how about stripping or cleaning a carb, if anyone could help explain. Also, someone suggested that the valve clearance might be wrong..is there a way of adjusting that?

Thanks everyone so much for the help,

Roketaman

underdun · 07-30-2009, 06:36 PM

try this

scooterfocus.com/scooter_troubleshooting_2.html

fiatguy85 · 08-03-2009, 08:12 PM

The valve clearance is a lot less likely to be the cause of it not running at all. The carb has these things inside called jets, which have tiny orifices which can become clogged. When you tear it apart, you can clean these out with guitar string or something similar. And usually you have a float and needle valve which has to be adjusted to a certain clearance. A carb rebuild kit would likely have instructions and any new gaskets and replacement parts. Or you can just strip it and clean the jets, and look up the adjustment somewhere. Just be sure to keep track of how everything goes back together, there may be a lot of parts in it.

06-29-2009, 04:16 PM	#1 (permalink)
RoketaMan Upright	engine wont start I was wondering if anyone could help me..I have a 4 stroke 150cc scooter and for some reason it wont start up. The engine cranks but it just wont start. Some background info, I've had problems with the engine trying to start up and it wouldnt idle, it would just die. I had poor power and performance on it (it was accelerating slow and going 10mph slower). Can anyone please help??

07-11-2009, 05:04 PM	#6 (permalink)
Bear Cub The Reverend Side Boob Location: Nofe Curolina	What's the plug look like when you pull it? __________________ Living in the United Socialist States of America.

07-21-2009, 11:50 AM	#11 (permalink)
telekinetic zomgomgomgomgomgomg Location: Fauxenix, Azerona	What color are the sparkplugs? __________________ twisted no more

07-30-2009, 06:36 PM	#14 (permalink)
underdun Upright Location: Eastern Canada	try this scooterfocus.com/scooter_troubleshooting_2.html __________________ If you don't stand behind our troops, feel free to stand in front of them.

06-29-2009, 04:32 PM	#2 (permalink)
shakran Tone.	if an engine cranks but won't start, you either aren't getting fuel, or you aren't getting spark. First, remove a sparkplug, hook it up to the plugwire again, and crank. If you don't see a spark, remove the plug wire and hold it against a metal bolt on the engine while cranking. Look for the spark. If you don't see it, you have an electrical problem. Start with the distributor, coil, and ignitor. If you do see a spark, but didn't when you had it hooked up to the plug, replace the plug, and make sure it's gapped properly for your engine. Assuming you have spark, take off a fuel line and crank the engine (obviously do not smoke, or have any open flame or hot items in the area when you do this, and do it outside so you don't burn down the garage.) If you don't see fuel spurting out, then you have a fuel delivery issue. Probably either the filter is clogged, or the pump is bad. Take off the fuel line before the filter to see if fuel is getting that far. Keep working backwards until you get to the pump to find the source of your fuel stoppage. Another possibility is that the timing is radically off, which would mean the spark is happening, but not when the fuel/air mixture is right for combustion. Try adjusting the timing backwards and forwards while cranking to see if you can get it started, and if you can, then time the engine properly with a timing light (available cheap at auto parts stores, and I believe NAPA and Advanced Auto will lend one to you.)

06-30-2009, 05:13 AM	#3 (permalink)
RoketaMan Upright	thank you so much!

07-11-2009, 05:01 PM	#5 (permalink)
RoketaMan Upright	Thank you so much! 1. I had an electrical problem and so I fixed it by replacing it with a new CDI box and a spark coil. 2. The scooter started up and drove fine for 25 miles. But now, it has problems starting up again. Prior to this though, my scooter would not idle (I would have to pull the throttle to keep it at a constant RPM). If I let go of the gas it would die. I've tried adjusting the idle on the carb but that didn't hlp. I'm thinking it could be the carburator? Is there anything else it can possibly be? Would buying a new carburator and replacing it fix it? Any help is seriously appreciated! Thanks!

07-12-2009, 04:44 AM	#7 (permalink)
Flinx Tilted Location: Canada	I wouldn't buy a new carb for it. They are fairly easy to strip down an rebuild and thats MUCH cheaper.

07-13-2009, 06:27 AM	#8 (permalink)
RoketaMan Upright	I get spark, it just doesn't wanna start up. I think something is wrong with the carb or something with fuel. If it is not the carb, what else could it be?

07-13-2009, 07:38 AM	#9 (permalink)
shakran Tone.	I think Bear was more going for the color of the spark plug. Is there any discoloration on the white part? Rediagnose from the start. Just because something wasn't broken when you checked it the first time, doesn't mean it didn't decide to die during the 25 mile drive. Make sure fuel is getting to the carb before you start stripping the carb down.

07-21-2009, 11:46 AM	#10 (permalink)
RoketaMan Upright	Alright Thanks..I put a brand new spark plug in and it gets spark. Once I start stripping down the carb, is there something I'm something I'm supposed to look for or clean? Thanks a lot for all the help!

07-22-2009, 06:52 AM	#12 (permalink)
Flinx Tilted Location: Canada	BUMP for the color of the plug, sooty black? Flaky white? Oily? The way a plug looks can tell you a lot of whats going on. As for the carbs, see my previous post about them. Oh I can't believe I forgot to mention one other thing. between the carbs and the cylinder there is a rubber piece, check that for cracks/leaks. My old 750 Seca RL had a startup problem for a bit till I discovered one of those rubber pieces had many cracks in it. Bit vague but I'm tired an burnt out right now

07-30-2009, 04:59 PM	#13 (permalink)
RoketaMan Upright	Alright, the spark plug is black when I pulled it out. The rubber piece is in tact between the carb and the cylinder. I don't know how about stripping or cleaning a carb, if anyone could help explain. Also, someone suggested that the valve clearance might be wrong..is there a way of adjusting that? Thanks everyone so much for the help, Roketaman

08-03-2009, 08:12 PM	#15 (permalink)
fiatguy85 Crazy	The valve clearance is a lot less likely to be the cause of it not running at all. The carb has these things inside called jets, which have tiny orifices which can become clogged. When you tear it apart, you can clean these out with guitar string or something similar. And usually you have a float and needle valve which has to be adjusted to a certain clearance. A carb rebuild kit would likely have instructions and any new gaskets and replacement parts. Or you can just strip it and clean the jets, and look up the adjustment somewhere. Just be sure to keep track of how everything goes back together, there may be a lot of parts in it.