115 V4 dead top cylinders.

drackley

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I've started this new thread since the last one seems to have resulted in the issue being spark related, and not fuel. 1994 v4 crossflow. New engine, carbs, power pack, and timer base. I just threw in a new set of plugs and after trying to keep it running I pulled the top plugs, and sure enough they are wet, but no carbon. Compression is great, all coils look new. I can put a spark tester on it a shoot four 1/2" bolts on cranking. I can put a plug on the wire and get spark at the electrode. But if the plugs are in, NOTHING! I can pull the plug wire and there is no difference. Is there something in common that would take out both the top plugs? Do the two stator coils each handle 1-2 and 3-4?
 

JB

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Re: 115 V4 dead top cylinders.

What happens if you squirt a bit of fuel mix in the top carb? RPM jumps up? Top carb is plugged up. <br /><br />Needs cleaning and overhaul. Might as well do both.<br /><br />Wet plugs are mostly meaningless. Engine turns over and pumps after ignition is turned off.<br /><br />Good luck. :)
 

drackley

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Re: 115 V4 dead top cylinders.

The carbs have been done twice. I put a rag over the inlet of the top carb, and had alot of gas load up, but it made no difference.
 

sparkroost

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Re: 115 V4 dead top cylinders.

put a timing light on it and see if it's firing at the same deg. BTDC. on the cylinders in question.
 

drackley

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Re: 115 V4 dead top cylinders.

Sparkroost: I've not heard of this "test" before. Can you enlighten me? Thanks
 

Walker

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Re: 115 V4 dead top cylinders.

Sounds like you have an electrical leak. You spark is leaking off somewhere before it gets to the sparkplug. Try this. Put all the sparkplugs in and hook up all spark plug wires. Fire the motor up at night and look for sparking around the all the ignition components and wires. Try to "carefully" look up under the flywheel too.
 

sparkroost

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Re: 115 V4 dead top cylinders.

ok... In my case I used a dial indicator with a magnetic base. Get a piece of metal to lay on the lower cowling and put mag. indicator on. Take plugs out and insert indicator in spark plug hole. (You are always supposed to turn flywheel clockwise, but for this you have to turn counter clockwise). Turn flywheel clockwise until indicator stops moving, then "0" indicator. rotate about 20 degrees more clockwise then rotate counter clockwise until indicator stops, should be at 0. Now rotate flywheel counter clockwise about 20 deg. then clockwise until the indicator reads .001 BEFORE 0. Scribe a line on flywheel in line with the timing pointer. Now move flywheel 20 degrees clockwise then counterclockwise until .001 BEFORE 0 degrees. Scribe line with pointer. You should now have 2 scribe marks on the flywheel. Inbetween those marks is ZERO degrees.<br /><br />Now this is all true IF your pointer is already calibrated to ZERO. If not you will use the above method to ZERO with one exception, you will adjust the pointer and use the timing marks on the flywheel.(turn clockwise to 1 deg. after TDC then c.c. until 1 deg. BTDC. When you can get the same reading on the indicator in both directions you will have found 0 degrees inbetween 1 plus and 1 minus).<br /><br />If you don't have an indicator, you can remove plugs, turn flywheel until piston reaches top, then mark flywheel at pointer with a chalk marker. That is a rough estimate of where 0 is though. From there you can measure the distance from 0 to 20 degrees on the timing marks then go to your mark and mark it that distance from 0. Now you have a mark for that cylinder set at 0 degrees and 20 BEFORE TOP DEAD CENTER(you will add your mark to the left of ZERO). Repeat this for the remaining cylinders.<br /><br />You now have 8 marks on flywheel in a bright color that is in strong contrast to the color of the flywheel.<br /><br />Stick timing light on #2 cylinder, start engine, shine light at pointer. You should see the mark you made on the flywheel and it should not flicker out of sequence or change where it's position is on the pointer.<br /><br />You may need to move your timing up by setting up the idle a bit to get the arm close to the stop.<br /><br />The second method will be good enough to check for spark. It will NOT be a true indicator of where those degrees are due to finding Top Dead Center can't be seen visually and needs proper equipment.
 

drackley

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Re: 115 V4 dead top cylinders.

Thanks Sparkroost. I hate to ask a dummy question but what is the relavance to 20 degrees? If the spark is jumping around (this would explain the engine stopping suddenly when I'm trying to keep it running on the 2 or 3 cylinders) would that be the stator? I hope it's not this new power pack!
 

clanton

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Re: 115 V4 dead top cylinders.

If it is a 1994 engine, the stator only has one charge coil for the ignition system. The timer base has 4 sensors. Cylinder 1 and 3 are on the stb side, 2 and 4 on the port side. If you are getting a 1/2 inch spark at all cylinders, check flywheel key. Does the engine run on the 2 bottom cylinders?
 

sparkroost

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Re: 115 V4 dead top cylinders.

There is no revelance to the 20 degrees. You just need to go past and come back to remove any slop.<br /><br />With your timing close to the stop you should be firing at 20-28 degrees. I just want to be able to see the mark on the flywheel. The whole idea here is to see that the other cylinder are firing at the same degrees before top dead center as #1. If you have a short somewhere the timing light will go out periodically when the arc finds a path to ground. <br /><br />You probally have a cracked coil, bad spark plug wire, or a poorly grounded coil with respect to battery ground.<br /><br />It is also possible that you have too much fuel!Has it ever backfired? If so, just as clanton suggests, you may have a sheared flywheel key.
 

drackley

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Re: 115 V4 dead top cylinders.

Clanton and Sparkroost: I've had the flywheel of many times during this ordeal. The keyway is fine, and it does run on the bottom two cylinders but just barely. It can sometimes backfire, but It's minor and I think can be attributed to beeing a bit rich from the choking to get it started. I'll check grounding. Is there a way to check the coils? I do have a PVA for my VM. I greatly appreciate you sticking with me on this guys. The engine was done three months ago, And I've been trying to get it running ever since as time allows, but the boating season here in the pacific northwet is running out. P.S. I have also checked the timer base, and it is better than speck. Cheers
 

drackley

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Feb 6, 2003
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Re: 115 V4 dead top cylinders.

Update: This evenings starter crankathon resulted in first checking the compression again. 130-135 on all cylinders. I then put the timing light on it and after having set the timing to 24 degrees at wide open cranking (as per other posts here) I find that throttle clsed timing is a good 5 degrees AFTER TDC. Winding this down to 4 degrees BTDC has resulted in it firing up as soon as the starter is hit. However I've still got nothing to speek of (running at well over 1200 rpm) on the top. As evidenced by removing a plug wire. A little gas shot into the top throat does race it up. Soooo. Can we agree that I now have a carb problem? **** things been gone through twice. Could it be that anti syphon valve at the tank?
 

sparkroost

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Re: 115 V4 dead top cylinders.

not necessarily. Could be a gasket air leak. Get a can of something flammable and squirt some around the intake when it's running. The engine will rev up when you find the spot.
 

clanton

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Re: 115 V4 dead top cylinders.

Do you have the wires from pack to coil in the correct position? You could remove large screw on side of float bowl to verify fuel is getting to carb.
 

Dhadley

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Feb 4, 2001
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Re: 115 V4 dead top cylinders.

Switch the top and bottom carb and see if the problem follows the carb.
 
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