After running fine for years my lo boy 185 won't start. It cranks away but I get no spark. Over the years I have bypassed the PTO safety switch and the clutch safety switch so those can't be the problem. Does anyone know of another kill switch that might cause no spark. I am thinking low oil pressure sensor but even looking at the ignition wiring diagram I can't see how or if this would cause a no spark condition. If I just disconnect the sensor would that bypass the sensor?
Cranks but no spark
- Thread starter aeginc77
- Start date
Yes, coil shows 12 v at positve and negative terminals. Points are new and I've checked gap 3 times. The fact that there is a continuous 12 v on coil negative tells me the points are not breaking the negative flow thereby not allowing the Hi voltage side of coil to charge. In other words, the circuit is continually open to ground. I am hoping that there is some safety switch that is causing this but only thing I can come up with is oil pressure sensor but I don't know if a faulty sensor will kill engine.
staninlowerAL
501 Club
Welcome to the Forum. First check: does the points arc when they open and close as you try starting the engine?
Second: tst's check for electrical power to the coil.
Third: Check the output from the coil center (tower) to ground then at the plugs.
When you have spark as described above the engine should start if there's fuel available, proper air flow and in time. JMHO Stan
Second: tst's check for electrical power to the coil.
Third: Check the output from the coil center (tower) to ground then at the plugs.
When you have spark as described above the engine should start if there's fuel available, proper air flow and in time. JMHO Stan
Thank you, but that's my problem. The points open and close and are gapped properly. There is 12V power to the coil but NO Hi Voltage from the center. Both + and - coil terminals show constant 12 V with ignition on.
Hi,
They have said on here that some new points have a clear coating on them, probably to keep them from corroding. The coating won't let power through the points. You can test the points with them closed and see if power is going through them. File the coating off with a point file, if it is there.
Wipe off all filings with a clean rag.
They have said on here that some new points have a clear coating on them, probably to keep them from corroding. The coating won't let power through the points. You can test the points with them closed and see if power is going through them. File the coating off with a point file, if it is there.
Wipe off all filings with a clean rag.
staninlowerAL
501 Club
Does the points fire when they open and close? If yes, then the coil is faulty (open circuit on the high voltage inductive current winding). BTDT, took me about 3 hours to figure it out the first time. FYI, the points must fire to ground to create the inductive current flow on the high voltage winding and to the plugs. I Replaced the coil and the engine started on the 3rd revolution and been running ever since then. Good Luck. Stan
Gary Dotson
501 Club
Your making the right checks but interpreting the results ass-backward. If the points were grounding, you would have no voltage at the neg. coil post. Clean the protective film off your contacts, as Glen suggested, make sure you’re adjusting the point gap on the high point of the cam lobe, you’ll be good to go..
Thanks, the issue is the points are grounding - when open they do not break the circuit hence the negative coil terminal always shows 12 v. I am going to remove distributor again and check my points installation
You are still, as Gary said, interpreting the results ass-backwards. If the points are grounding, whatever is connected to them will have the voltage pulled down to zero. Your problem is that they are acting open whether physically open or closed.
staninlowerAL
501 Club
You can verify that the problem is at the points by removing the neg connection from the coil neg to the post on the side of the distributor and test to see if the current is off and on as you turn the the engine to start. Your tester should show alternation current flow just like the points would if they were breaking correctly. You could have a ground internally in the distributor or the post connection from the coil is shorted to the base of the distributor. Stan
I think I must be saying something incorrectly. Turning over the engine has no effect on the 12v on either positive or negative side of coil. A test light connected to negative side of coil should go on and off as points open and close. My points are indeed opening and closing but the 12v at negative terminal of coil remains w/o going on and off, hence the secondary coil of the coil never builds up hi voltage charge. The negative lead from coil goes to distributor and connects to condenser and points and turing the distributor should break the 12v circuit but this is not happening even though the points open and close. Somehow/somewhere the negative (ground) is bypassing the points.
staninlowerAL
501 Club
That's the reason I suggested that you remove the wire at the connection to the distributor. If your test light works off and on as the engine is turning, the ground is through some part of the distributor (like the plastic isolation for the screw post). Might be something on the points mechanism that is touching the housing. And your oil pressure sensor should not be a part of the problem but temporarily disconnecting the power supply from it won't hurt anything. Stan
Thanks. I think we are on same page. Something in the distributor is touching something it should not. I will remove distributor (prestolite) and examine the points installation more closely. Thanks for the info on the oil pressure sensor. I initially thought one of the safety switches might be causing the problem.
staninlowerAL
501 Club
staninlowerAL
501 Club
I done a little more searching but did not find any reference to the Prestolite distributor in any of the number series manuals that I have. I did go look again at the picture that I posted above and got a better image of it which is attached below. If you view it in full screen mode you can read the parts numbers better and notice that the contact points has a different IH part number for the IH distributor vs the Prestolite distributor. This info is in TC37F Rev 6, 8-79 and is all that I found. Someone with more reference material might be able to add to the application info for the C60 engine. I did not look in the Number Series service manual so that might have some info. Bottom line is there is a different IH part number for the contact points for the two different distributors. 
Stan
StanAttachments
Thanks for all the help. Yes the points for the Prestolite distributor are not the same as the IH or Delco. I found this out the hard way after initially ordering a set from Amazon. Unfortunately, they were not for a Prestolite distributor! I had to go to Quality Farm Supply to get correct ones and recieved great quick serivce! I'll let you know how this turns out - its my project for today!I done a little more searching but did not find any reference to the Prestolite distributor in any of the number series manuals that I have. I did go look again at the picture that I posted above and got a better image of it which is attached below. If you view it in full screen mode you can read the parts numbers better and notice that the contact points has a different IH part number for the IH distributor vs the Prestolite distributor. This info is in TC37F Rev 6, 8-79 and is all that I found. Someone with more reference material might be able to add to the application info for the C60 engine. I did not look in the Number Series service manual so that might have some info. Bottom line is there is a different IH part number for the contact points for the two different distributors.
Alan
staninlowerAL
501 Club
Progress! And Your welcome, glad to help! I've got a lot of good help from the forum members. Stan
Let there be spark! I removed the distributor and inspected the points installation. Turns out one of the screws that attaches the spring clips holding the distributor cap on was a bit too long and one of them made contact with the spring steel holding points against the cam. this let the current flow bypassing the points. We now have coil control and spark at the plugs! Now on to the fuel system! Thanks for everyone's help!
staninlowerAL
501 Club
Yup, sometimes the little things will get you. Glad you got it figured out. Stan