Weird issue, cart won’t stay running

[Largemouth21]

Hey guys,
Working on my bosses ez go with a robin eh29c. So the issue is that cart has an extremely hard time starting, and if started won’t stay running for very long. It’s got compression, because it runs great when it runs. It’s got fuel, carb is spotless trust me and even using starting fluid doesn’t help. The spark is snapping and bright blue. When I check the plugs after trying to start it for a while, they are dry meaning it is sparking. I can put fuel down the plug hole or even in the carb and it doesn’t want to start. Plugs are pretty new, fuel lines are new, I adjusted valves, fuel pump works properly and fills carb bowl, I cleaned all grounds I could find and tested continuity of battery cables. But It is just about impossible to get to stay running. I was wondering if it could be the pulasar unit, from my understanding it tells the plugs when to fire. So if I do happen to get it running it slowly kinda loses power and eventually slows to a putter and quits... any advice?

[CP241]

What kind of compression do you have in each cylinder? "Has compression" and "has good compression" can be completely different things. Should be 165-170psi in each cylinder for a happy engine.

[newtjl]

This is just thinking out loud, but to me it looks as though you have been pretty thorough in checking the usual problem areas. I am inclined to think there may be a timing issue just by your post. Like perhaps the timing is off when it is hard to start, finally hits at the correct time and it starts and runs, then eventually falls off again. A couple of quick things to check. 1. When you are having problems starting, put a test light on the positive and negative terminals of your coill as you turn the engine over. The test light should flash. If it is flashing you are getting spark (not necessarily at the correct timing). 2. Check the timing marks and the condition of your timing belt. I am thinking that your timing belt may be slipping resulting in spark and fuel, just not at the correct time.

I think if the pulsar or the igniter were bad, you wouldnt be getting spark at all. If you are for sure getting spark, for sure getting fuel, and for sure have plenty of compression, the only thing remaining is the timing of all three occurring at the same time.

Just a couple of quick things to check!

[Largemouth21]

Originally Posted by newtjl

This is just thinking out loud, but to me it looks as though you have been pretty thorough in checking the usual problem areas. I am inclined to think there may be a timing issue just by your post. Like perhaps the timing is off when it is hard to start, finally hits at the correct time and it starts and runs, then eventually falls off again. A couple of quick things to check. 1. When you are having problems starting, put a test light on the positive and negative terminals of your coill as you turn the engine over. The test light should flash. If it is flashing you are getting spark (not necessarily at the correct timing). 2. Check the timing marks and the condition of your timing belt. I am thinking that your timing belt may be slipping resulting in spark and fuel, just not at the correct time.

I think if the pulsar or the igniter were bad, you wouldnt be getting spark at all. If you are for sure getting spark, for sure getting fuel, and for sure have plenty of compression, the only thing remaining is the timing of all three occurring at the same time.

Just a couple of quick things to check!

Thank you very much! That is super helpful for my diagnosis. I’ve worked on other small engines, but none with a pulsar. So is the pulsar what controls ignition timing? I will pull the timing cover off and take a look.

[trig123]

Originally Posted by Largemouth21

Thank you very much! That is super helpful for my diagnosis. I’ve worked on other small engines, but none with a pulsar. So is the pulsar what controls ignition timing? I will pull the timing cover off and take a look.

I wouldn't be pulling the cover off. Pulser can be checked very easy. If its running then that is not your problem. Also the pulser is not under the timing cover.
These timing belts can be adjusted to remove what slack might have happened over time without taking anything off. There is a plug on the cover to do this with.
I would do as CP241 suggested yesterday and post back results.

[Largemouth21]

Originally Posted by newtjl

This is just thinking out loud, but to me it looks as though you have been pretty thorough in checking the usual problem areas. I am inclined to think there may be a timing issue just by your post. Like perhaps the timing is off when it is hard to start, finally hits at the correct time and it starts and runs, then eventually falls off again. A couple of quick things to check. 1. When you are having problems starting, put a test light on the positive and negative terminals of your coill as you turn the engine over. The test light should flash. If it is flashing you are getting spark (not necessarily at the correct timing). 2. Check the timing marks and the condition of your timing belt. I am thinking that your timing belt may be slipping resulting in spark and fuel, just not at the correct time.

I think if the pulsar or the igniter were bad, you wouldnt be getting spark at all. If you are for sure getting spark, for sure getting fuel, and for sure have plenty of compression, the only thing remaining is the timing of all three occurring at the same time.

Just a couple of quick things to check!

Ok update I loosened up the timing cover and looked inside, the belt looks decent, it isn’t all cracked or anything. There is not a lot of play in the belt and I couldn’t get it to slip even though I tried. I don’t want to take the clutch off if I don’t have to. Is there any way to confirm timing without removing the cover all the way? I’d rather not take the clutch off....

[Largemouth21]

Originally Posted by CP241

What kind of compression do you have in each cylinder? "Has compression" and "has good compression" can be completely different things. Should be 165-170psi in each cylinder for a happy engine.

When the cart runs it runs fine, I am certain it is not a compression issue.

[Largemouth21]

Originally Posted by trig123

I wouldn't be pulling the cover off. Pulser can be checked very easy. If its running then that is not your problem. Also the pulser is not under the timing cover.
These timing belts can be adjusted to remove what slack might have happened over time without taking anything off. There is a plug on the cover to do this with.
I would do as CP241 suggested yesterday and post back results.

Do I have to completely remove the pulsar to test it?
EDIT: ok guys I tested the continuity of the pulsar, I got 20 ohms on the 200 ohm setting. I take it that’s not the intended spec? I made sure it wasn’t shorting to ground also. I checked the wire that goes to the pulsar and it is grounding like it’s suppsoed to. So is my pulsar bad? If so is the HEI conversion the best choice? Keep in mind I still DO have spark to the plugs, but perhaps it’s at the wrong time....

EXIT: so I checked the ac current of the pulsar as well, on the 2V setting I got .115. Does that mean it’s not enough? Still weird that it ALWAYS sparks but only sometimes runs. Any help would be appreciated

[CP241]

Is it really that hard to do a 30 second compression test? I'd be curious hot vs. Cold motor also.

Just because it runs doesnt mean compression is in spec. I've had these motors "seem" to run fine at around 100psi they just dont run for long or particularly well (meaning they're smooth but not making the power they should). It's worth a quick check just to rule it out if nothing else before you chase your tail chasing spark for weeks and come up.with nothing conclusive.

Just my .02 I dont have your cart in front of me but checking to see if spark exists, compression, and if it will start by squirting a little gas in the sparkplug holes is the very first thing I do anytime I start looking at a cart, rule out the basic easily measurable things first before digging in too deep. But that's just me.

[Largemouth21]

Originally Posted by CP241

Is it really that hard to do a 30 second compression test? I'd be curious hot vs. Cold motor also.

Just because it runs doesnt mean compression is in spec. I've had these motors "seem" to run fine at around 100psi they just dont run for long or particularly well (meaning they're smooth but not making the power they should). It's worth a quick check just to rule it out if nothing else before you chase your tail chasing spark for weeks and come up.with nothing conclusive.

Just my .02 I dont have your cart in front of me but checking to see if spark exists, compression, and if it will start by squirting a little gas in the sparkplug holes is the very first thing I do anytime I start looking at a cart, rule out the basic easily measurable things first before digging in too deep. But that's just me.

You make a valid point sir! I will ask my boss to borrow a compression gauge. I am just curious as to how it would run sometimes for 30 seconds or so, and it runs good for that time, and suddenly it just sputters out and won’t start. Thank you for the help I hope I can solve this