Could it be spark plug?

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, and others.
As quoted from the list: A spark plug check can be carried out in the following manner; remove plug from engine, reconnect the spark plug into the plug boot, touch the plug thread to the engine block or exhaust header, pull-start and check if plug is firing. NB. Even though a spark may be visible, it may not be strong enough to spark under compression.
 
rcgasser said:
As quoted from the list: A spark plug check can be carried out in the following manner; remove plug from engine, reconnect the spark plug into the plug boot, touch the plug thread to the engine block or exhaust header, pull-start and check if plug is firing. NB. Even though a spark may be visible, it may not be strong enough to spark under compression.
Click to expand...
Thank you gasser. Appreciate your help! You've been really helpful!
 
No problem at all I have been there so I know how it is that's what this forum is for I have received tons of help from members here myself I would be lost without them.
 
ImminentFailure said:
Have you tested that you are still even getting a spark now that it's clean and your flywheel gap is good? Should be able see it sparking following the standard method to test the plug outside the engine. Carb could be shot, could be something worse inside the engine itself. IF you fill the primer bulb, and shut all your needles (turn to full closed) does it empty the bulb as you pull to start it? Don't forget how many turns in you have to make to close them so you can return to last tune if it doesn't help.

Have you checked your killswitch. I Assume you have one because these things shouldn't be operated without it. IF that's preventing spark, could explain no spark when you do a spark test.
Click to expand...
Ok thanks for the tips!

1. Yes I test the spark plug and I see sparks but again it may not be strong enough but its good to know that my coil is igniting it :D Thanks!

2. Closing all the needles all the way into the carb and pull starting does not empty the primer, is that good?
 
rcgasser said:
No problem at all I have been there so I know how it is that's what this forum is for I have received tons of help from members here myself I would be lost without them.
Click to expand...
Yeah! just that when your new to something, it just seems 10 time harder then it is :D
 
rcgasser said:
Yes it is but when you do get it right with help on your own it is 10 time more gratifying.
Click to expand...
Very true, rcgasser can you help point out what eminentfailure is trying to say regarding closing all the needle and pull start should release fuel from the primer? Is it suppose to do that? When it does, is that bad? What is right and what is wrong?
 
rcgasser said:
Sorry that part I can not speak on I will have to let one of the professional step in here and answer that one for you.
Click to expand...
I hope they will chime in. Sometime they don't because they are too busy or think I ask too much question :(
 
So, it sounds like you confirmed spark. Sounds like you're getting fuel. Start checking for loose bolts. Specifically, the carb and intake bolts. If those are fine, check the head bolts. Then check the exhaust bolts. While you're checking the bolts, look for damaged gaskets.
 
The primer bulb not emptying with all needles closed it correct. It should NOT let any fuel into the carb when the venturi create the vacuum. The reason for the test is sometimes these junky carbs will get the needle screw springs bound up, or a bit too long. What happens is 'fully closed' really isn't fully closed, and all of a sudden your base line for # of turns is off. When I was new to the engine, I was way off from normal starting needle turns to get it to even run after checking all other turning tips from DDM / forums. When I Closed all my needles, it was still open on the low.

Testing for spark also confirms your killswitch isn't faulty, causing a contact interrupt. That mixed with the flywheel gap being good, should net you strong spark. If you haven't already, I would introduce a new spark plug vs. just the cleaned /re-gapped one just for extra insurance in the troubleshooting phase. It's a cheap costs to remove it from the equation.

Was it at idle warming up and just died?

Did it race (RPMs ran up) first, or just bog out?

Is the choke plate staying to where you set it, not so loose it may auto close?

MY stock carb idled best at only 1/2 turn out on the low, the stock starting points on DDM website failed for me. I was scarred of lean issues, but some baja guys at my local track who easily had $10,000 into their 5 baja's tuned it and said it sounded good.
 
Last edited by a moderator:
ImminentFailure said:
The primer bulb not emptying with all needles closed it correct. It should NOT let any fuel into the carb when the venturi create the vacuum. The reason for the test is sometimes these junky carbs will get the needle screw springs bound up, or a bit too long. What happens is 'fully closed' really isn't fully closed, and all of a sudden your base line for # of turns is off. When I was new to the engine, I was way off from normal starting needle turns to get it to even run after checking all other turning tips from DDM / forums. When I Closed all my needles, it was still open on the low.
Click to expand...
What else could be wrong with my engine? Please help!
 
Deluge said:
So, it sounds like you confirmed spark. Sounds like you're getting fuel. Start checking for loose bolts. Specifically, the carb and intake bolts. If those are fine, check the head bolts. Then check the exhaust bolts. While you're checking the bolts, look for damaged gaskets.
Click to expand...
What I notice is my carb is dirty. I don't know if this is normal. Kinda like real car's engine... you know how real car engine collect black particle and oil over the engine? Kinda like that, is that normal? So far from what I see all the seals and bolt are fine...... what else could be wrong?
 
Deluge said:
So, it sounds like you confirmed spark. Sounds like you're getting fuel. Start checking for loose bolts. Specifically, the carb and intake bolts. If those are fine, check the head bolts. Then check the exhaust bolts. While you're checking the bolts, look for damaged gaskets.
Click to expand...
When you say bolt your talking about the screws holding those pieces right? I think the intake bolt are the screws that goes to the carb to hold the intake on the carb?
 
ImminentFailure said:
That could be a sign of a leaky gasket if it's really oily and caked on from only a few runs.
Click to expand...
I've run it since i purchased it on august ... but I haven't really push it to the limit (push to the limit to me is all out WOT for a long period of time). Lately I have been doing straight run tunning... and the engine seems to die when hot after a long hard run. Once you shut it off after a hard run you may want to wait for it to cool before being able to restart again. Now it simply won't start no matter what I do....
 
Last edited by a moderator:
ImminentFailure said:
The primer bulb not emptying with all needles closed it correct. It should NOT let any fuel into the carb when the venturi create the vacuum. The reason for the test is sometimes these junky carbs will get the needle screw springs bound up, or a bit too long. What happens is 'fully closed' really isn't fully closed, and all of a sudden your base line for # of turns is off. When I was new to the engine, I was way off from normal starting needle turns to get it to even run after checking all other turning tips from DDM / forums. When I Closed all my needles, it was still open on the low.Testing for spark also confirms your killswitch isn't faulty, causing a contact interrupt. That mixed with the flywheel gap being good, should net you strong spark. If you haven't already, I would introduce a new spark plug vs. just the cleaned /re-gapped one just for extra insurance in the troubleshooting phase. It's a cheap costs to remove it from the equation.

Was it at idle warming up and just died?

Did it race (RPMs ran up) first, or just bog out?

Is the choke plate staying to where you set it, not so loose it may auto close?

MY stock carb idled best at only 1/2 turn out on the low, the stock starting points on DDM website failed for me. I was scarred of lean issues, but some baja guys at my local track who easily had $10,000 into their 5 baja's tuned it and said it sounded good.
Click to expand...
I started the engine after a couple weeks of not running due to my cups and differential repair. I let it idle for 30 sec and then I slowly drive off. Reaching the road I slowly accelerate and went faster and faster. Turn around with WOT. I think it bogged down and then pff.... I safely pull it to the side while the car is still rolling. The choke does stay where I set it and doesn't move out of set.
 
Last edited by a moderator:
ImminentFailure said:
If you put your thumb over the spark plug hole, and pull do you feel compression?
Click to expand...
Yes sir... and If I remove my thumb I will smell gas.... and I think gas splatter out too....
 
Last edited by a moderator:
Back
Top