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620 wont start. Getting fuel and spark


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Hoping Ratsun can help on this one. Took my r1 carbed l20 on its maiden voyage and had to call a tow truck. I was driving along and it died on me. Would not start back up. Thought it might be flooded so I waited 20 mins and did the ole floor it and crank. No dice. 

What do you guys think it could be? I'm still on points ignition. Could it not handle the extra fuel of the R1s? I bought a 78 datsun disti and box on ebay but would rather sort this out before I install that just to be sure.The carbs have 1.8mm main jets and I'm out 3 and a half turns on the idle mixture screws. I'm using the stock fuel pump. Engine is completely stock. I have + on the balIast. I put a test light on the coil and it alternates + and - when cranking and a solid + when just the switch is on. The spark plug wires flash + when I crank it.

 

I even swapeed another points disti off my spare engine with no luck.

Verified fuel pump is pumping gas.

 

Should I install the 78 disti and box to be sure its not a spark issue?
 

Thanks
MantisX 

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If the starter rotates the engine... then it's cranking.

 

It it cranks but doesn't start... it's just not starting. Big difference.

 

 

 

Pull the coil wire off and hold near ground and crank it. Spark? Yes or no?

 

If you have spark then it has to be fuel related (too much or too little)

 

If you suspect flooding remove the plugs and dry them. While they are out crank the motor over to dry out the cylinders. Replace plugs and try starting.

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Haha, sorry Mike, I thought about it right after I hit submit. It wouldnt let me edit the title.

 

I verified spark by taking #1 spark plug out and arcing off the valve cover. I got a blue arc when I did that. I guess its somewhere in the carbs, but what about R1 carbs would make an engine fail to start? I drained the bowls of all 4 looking for any contaminants, nothing. I didnt sync them or anything before heading out but hell they never ran funny either. I guess ill pull them but ill be honest, I dont know what im looking for. I can smell gas when I crank it. The only thing I changed on the carbs  were the main jets(1.8s) and the idle mixture screws 3 and half turns out.

 

Thanks all

MantisX

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I drove it maybe a total of 15 miles. Went about 2 miles from my home and I stopped and put gas in it. The rest of the time I was driving it. Was cruising when it felt like I lost power. All downhill from there. Hasnt started since.

 

Ill also add, it backfired out the exhaust once at the beginning of the trip but I chalked it up to the carbs not being synced.

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Will pick up some starter fluid tomorrow. It acts like it wants to fire when cranking but never does. Ive tried choking them while it tries as well. Tomorrow if all else fails, im gonna put the 32/36 back just to see if itll start to rule out the R1s.

 

MantisX

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Does it fire or not? Fire doesn't mean "start and keep running", it means one or more cylinders spark off.

 

If it runs momentarily on the starting fluid, it indicates a fuel problem. Not necessarily the carbs though - it could be a fuel pump or filter issue. You can test that.

 

If it doesn't run for half a second on the starting fluid, you have other than a carburetor issue.

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Haha, sorry Mike, I thought about it right after I hit submit. It wouldnt let me edit the title.

 

Thanks all

MantisX

 

No problem, I fixed it. You should be able to edit the title by selecting EDIT then USE FULL EDITOR to access the title line, make your changes and then SUBMIT. 

 

 

15 miles would tell me that things are running fairly well. The plugs may have carboned up if running too rich? causing a hard restart. Pull and check/clean them.

 

Another thing is the ballast. It's by passed during start but when key is released it flows through it. If loose wire or open it's just like turning the ignition off. Briefly jumper a wire across the ballast. If it starts up this may be the problem.

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Jumped the ballast with no luck. Im starting to think maybe its not a carb issue because gas is getting to the plugs it seems. So ive shifted to electrical. If I unhook my fusible link, I shouldnt have power anywhere right? In my case, with an unhooked fusible, I can still crank it and all my lights, headlights, wipers, radio etc still work. Also when I tested the spark, it was blue but wasnt very big. Should it be a big very visible spark? 

 

MantisX

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That is odd. Everything but the starter goes through the fusible link.

 

Sure you have the link? Check the + battery cable to the starter... there has to be another supply jumpered onto it to supply the fuse and ignition switch.

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Pretty sure. So I checked voltage at the fuse box. With the switch on, the left 3 fuses have 12v. The right 3 have 0.05v. Is this normal? Please say no so Ill have something to go off LOL

 

Edit: Scratch that, tested them again and I got 12v......... Maybe my crappy HF voltmeter.

 

MantisX

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