135hp 1973 Electrical Problem, w/ video.

[OperativeK]

Freshly rebuilt motor having a strange problem. All new coils and I have spark on all 4. The spark seems kinda low on number 4 and unusually high on number 2. Can anobody please tell me what might be the problem. It runs great out of the water but today I took it to the lake and it bogs down. I have compression of 150 on the two cylindars that just got rings and the ones with pistons and rings .30 over, they have 135. Wondering if after breakin the compression should go up. <br /><br />Here is the video:<br /> http://opk.gotdns.org/johnson motor problem.wmv <br /><br />You can see the over spark on two and then I remove the plug wire from 4 and it bogs some. Before it didn't seem to change at all. I had taken one coil and put it on the other and now it seems slightly better. Recommendations please? -Thanks Mike

 

[R.Johnson]

Re: 135hp 1973 Electrical Problem, w/ video.

That 1973 was kind of a high strung engine. Does it have original clyinder heads? What piston's did you use on the rebuild? It sound's like an ignition sensor problem, but I wonder about that spread in compression numbers. You most likely will not gain 15# with a break in. Check those cylinder heads, and post back. Dhadley is the man you want here.

 

[Tom Scully]

Re: 135hp 1973 Electrical Problem, w/ video.

There is a problem with the connection between the spark plug and the plug wire. Check the plug cap in the boot, is it a clean connection?, is there grease inside the boot? <br />When you switched coils and the wire did the spark still jump past the same plug? On that year motor, I believe the wires are attached to the coils permanently so when you move the coils the wire goes with it?

 

[OperativeK]

Re: 135hp 1973 Electrical Problem, w/ video.

R.Johnson: It has original cylindar heads, I used Wisco pistons on the two bored over to .30. I didn't find out tell later that Wisco wasn't a good choice, would it be better to pull them out?<br /><br />Tom: Im going to go ahead and replace the plugs even though they are new looking at the manual all the plugs I see have the electrode and Im running plugs that do not have it. <br /><br />What is the recommended plug?, and thanks for the reply fellas. Im also going to pull the flywheel and check the timing etc. Any recommendations? How do I get hold of Dhadley?, is he usually around on the forum?

 

[Tom Scully]

Re: 135hp 1973 Electrical Problem, w/ video.

The plug without the electrode is for continuous high speed operation, it should not be a problem unless you troll allot.<br />It's either a bad plug , bad plug wire or possibly both. Moving the components around should tell you which.<br />Did you change the coils (and wires) between 2 & 4 and if so did the spark still jump past the same plug?<br />Dh is usually around on the forum.

 

[RobsTV]

Re: 135hp 1973 Electrical Problem, w/ video.

You will have lower compression if you punch out a cylinder .30, (you have increased the size of combustion chamber), so that sounds about right. <br /><br />Plugs in use here also have no ground electrode, and that is what it calls for in manual (no plug gap).<br /><br />Glad to see you were at 150 PSI stock, since that is about what my stock 135HP tests out at, and I thought something was strange with it so high.

 

[OperativeK]

Re: 135hp 1973 Electrical Problem, w/ video.

Tom: I replaced the plugs and I changed the coil from original spot 3, to 2 and the problem followed it, so I put on one of the old coils and RPM picked up but now it is trying to backfire every so ofter and 4 is still getting little spark, weak. <br /><br />RobsTV: Yes 150psi on the stock at .20 and for the .30 they are getting 135psi. I thought 150 was high too.<br /><br />I'm probably going to replace the powerpack next. I took the flywheel off and everything looks fine. Hope DH can shed some light on this if he sees the post. Thanks fellas. By the way the coils were all brand new would it be strange to get a coil that would do that?<br /><br />Also I'm getting black sludge out of the exhaust from what Im guessing is fuel not burning. Also just to mention when I take the cap off the coil that is over sparking it shocks the hell out of me!

 

[OperativeK]

Re: 135hp 1973 Electrical Problem, w/ video.

What is the trick to the timing on these motors? I have done the sync thing but is there really much of a way to adjust the timing. It not like my Merc with a timing belt and distributor. Please anybody with knowledge of timing adjustments on this motor?