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Sokniw

Spark Issues, 8hp k181, 75' B80

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So i have been rebuilding this engine on my wife's grandpas B80, Got the new piston in, got it to turn over, Starter fried... got a new starter, couldn't get it to start, i had spark, but fuel just wasn't getting to carb, So i ended up replacing Carb and Fuel pump. Replaced those, and then it had life i was getting it to spit and sputter but never run than it just stopped trying to start. The Little rubber gasket on the bottom of my gas tank was all rotted out so i decided to order it thinking maybe its not getting steady supply of fuel. 

FIxed that and then all my problems started. 

At first i couldn't get it to even turn over, i was testing everything with a voltmeter, Coil showed volts when i pushed the clutch in i thought ok thats right. It was good at the Solenoid, battery was good and charged, i could get it to turn over by jumping the coil. But i realized that for some reason the safety switch on the clutch was not engaging so i had to shove a little metal plate in there to get it to make contact. During all this i also change the ignition breaker.

So now i got it work and turning over, but the thing will not breathe life, so i went to check the spark, I pulled it out, grounded it to the block, and i get 1 spark on when i first turn it over and then nothing after that, But it also sparks again when i disengage the key. 

 

So im stumped, i am going to replace the coil/wire since its cheap enough, maybe even throw the old ignition breaker back on it. But any thoughts would be greatly appreciated. 

 

 

Edited by Sokniw

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Key switch.

Use your volt meter and check for voltage at the positive side of the ignition coil. There should be CONSTANT voltage with the key in the Run and Start positions.

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Ill check with the key on, cause before i only got a reading at the coil when i pushed the clutch in. 

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1 hour ago, Sokniw said:

Ill check with the key on, cause before i only got a reading at the coil when i pushed the clutch in. 

Sounds like you have the coil + switched with the Start wire.

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Alright little update, i went through and realized that My Points was not adjusted right so now i am getting a nice steady strong spark. 


But after replacing the fuel pump and the Carb, i still cant get any life out of it. 

My stepdad was over on fathers day and said the timing might be off, i do not see a timing mark on the flywheel maybe somone can direct me int he right direction on what the next steps i should take with this? 

 

I figured that even with bad timing i should still get it to pop or something. Possibly defective fuelpump, when i have the fuelpump fuel line disconnection from the gas tank should i feel a suction or would it be too faint to feel it? i have good compression in the cylinder, good spark, i even poured gas into the cylinder too see what would happen and i still got nothing. 

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Timing is controled by point gap on the Kohlers.

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Would and could this just make it not want to start at all? or do you think it would still try to spit and spudder even if the timing was that far off. 

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On 6/10/2016 at 7:14 AM, Sokniw said:

i get 1 spark on when i first turn it over and then nothing after that, But it also sparks again when i disengage the key.

Thought you had spark when cranking and letting off the key but that's it? Make sure you have constant voltage to the positive side of coil while the key is in the Run and Start positions. Was this issue ever fixed? Points gap off will not do this and adjusting them will not fix this.

Points gap timing off should still try and fire the engine. It may not run great but should still fire if you are getting spark.

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Well the moment i adjust the points gap just eyeballing it, i got a constant spark, before the spark was inconsistent. Now that i adjust the points (not to specific .020) it sparks like it should but i will adjust the timing to specs. 

 

But i put a new fuel pump and carb, and the carb was getting gas when i tried to start it i got some sputters and than it just stopped trying to start, thats when i changed out the points and started having the spark issue not knowing that the points need to be adjusted to spec (learning while i go) So now i am back to square 1, got spark and it doesn't try to even spit or sputter. just turns over. 

Edited by Sokniw

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On 6/10/2016 at 7:14 AM, Sokniw said:

So i have been rebuilding this engine on my wife's grandpas B80

Is it possible the cam is off a tooth or two?

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It could be possible, I am by no means a mechanic, i am using this project to learn and broaden my skills. I blew a rod in it, when i replaced the rod/cylinder all i did put the rod/cylinder back on the crankshaft without trying to move anything other than separating the block from the oil pan. 

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any way to tell if it did skip a tooth. Another odd thing is that when it tries to turn over and does spit and sputter it causes the start to over spin like its spinning to fast for the  starter but the engine never starts it just spits and sputters. 

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Turn the engine over slowly and see when the points open relative to the position of the timing mark on the flywheel.  This is the mag timing instruction but battery/points is same procedure

Capture.JPG

Edited by pfrederi

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I will give it a go this weekend and see how i fair out. thanks 
 

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I can't seem to find the S through the timing hole, i found the t but no s

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Have to 16hp engine never did find those mark on either of them and had to resort to paint stick. I was told with spark plug out roll engine around by hand with finger over hole. When you feel the most pressure is the spot. Might even help you locate mark too

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i mist have something else going on. Can't even get it to pop. Purl pump is pushing gas but I don't know of ots getting through the carb. Its a brand new carb and fuel pump. I got a spark and adjusted the points gap a million times. What pulls the gas through the carb?

to test the fuel pump I took the carb off and turned it over and gas started coming up through the line that goes to the carb, the carb has gas in the float. I'm puzzled it just doesn't try to start. Just turns over

 

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Sorry I had so many problems posting earlier I'd just could not help. Start by making sure you are getting good spark. Make sure you have condenser and points on same terminal that is nearest carb.

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spark is good, I did t change any of the wiring when it was working fine before it blew a rod.

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Spray some starter fluid down spark plug hole and see if you get it to cough or even start up. If not you might need to pull flywheel to see if key got sheared when you threw that rod.

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On 6/21/2016 at 10:51 AM, Sokniw said:

replaced the rod/cylinder all i did put the rod/cylinder back on the crankshaft without trying to move anything

So you removed the broken rod and installed a new rod, piston and rings, did you stagger the ring gaps? Have you put your thumb over the spark plug hole and cranked it over to see if the compression is strong? Since it ran well prior to throwing a rod, why did you change the fuel pump and carburetor? Did you check the movement of the valves while the head was off to be sure they are closing?

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I was this frustrated back as a teen. An old 6HP Tec would thump at the rope pull and lose spark. I had that flywheel off 50 times. II just hadn't torqued the nut... If your battery (-) is at the engine and the battery(+) is at the coil (+), you should have a strong spark and you say that you do. You've checked the points. I'd hang a fuel bowl above the carb to ensure the bowl is full using FRESH gas and to rule-out the pump, tank, etc. . It's a rebuild so we can expect compression but I'd squirt a little oil in the plug hole to make sure. Squirt some Gumout or similar liquid into the carb throat and fire the starter. If you don't get a strong kick, it's either spark or cam timing as the list has suggested. Check for a sheared flywheel key or it's back in the engine to check the cam timing. You might want to check the valve lash before you dig that far. Maybe you'll have it sorted to strong running on the 4th!

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On 6/27/2016 at 8:28 PM, 953 nut said:

So you removed the broken rod and installed a new rod, piston and rings, did you stagger the ring gaps? Have you put your thumb over the spark plug hole and cranked it over to see if the compression is strong? Since it ran well prior to throwing a rod, why did you change the fuel pump and carburetor? Did you check the movement of the valves while the head was off to be sure they are closing?

 

The valves were opening and closing, one of the valves seem to shut really hard (hope that makes sense). I changed out the Fuel pump and carb, because i feel the old ones sat to long i was just trying to eliminate any other errors that could be going wrong with it.  I have really strong compression i do not have a tester, but i feel it the compression is good. 

On 6/27/2016 at 3:07 PM, Thisguyisnew said:

Spray some starter fluid down spark plug hole and see if you get it to cough or even start up. If not you might need to pull flywheel to see if key got sheared when you threw that rod.

 

 

I got it to spit and sputter 1 time after changing out the Fuel pump and carb. Now it doesn't even try, i poured a little gas down the cylinder and i got one pop out of it. and thats it. I will look into this. Cause i am starting to think something more is going on than the basic mechanics of it all. 

On 7/3/2016 at 6:42 AM, Tuneup said:

I was this frustrated back as a teen. An old 6HP Tec would thump at the rope pull and lose spark. I had that flywheel off 50 times. II just hadn't torqued the nut... If your battery (-) is at the engine and the battery(+) is at the coil (+), you should have a strong spark and you say that you do. You've checked the points. I'd hang a fuel bowl above the carb to ensure the bowl is full using FRESH gas and to rule-out the pump, tank, etc. . It's a rebuild so we can expect compression but I'd squirt a little oil in the plug hole to make sure. Squirt some Gumout or similar liquid into the carb throat and fire the starter. If you don't get a strong kick, it's either spark or cam timing as the list has suggested. Check for a sheared flywheel key or it's back in the engine to check the cam timing. You might want to check the valve lash before you dig that far. Maybe you'll have it sorted to strong running on the 4th!

 

 

Thank you for the reply. I will probably end up pulling the flywheel when i get the chance. To many projects going at once, trying to get my vintage camper restored so i can take the family out camping this summer before school starts again. 

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