fire frustrations

[roofcock]

hello all and thank you for viewing my problem. first a little history. i bought this boat at the end of the season last year. it is an old barnacle barge (tri hull) bass boat. i bought it to replace the existing boat i started to recondition when i realized it was cheaper to buy another cheap boat. this boat has a 1976 johnson 85 horsepower outboard. the problem is the spark. from the rear of the motor the bottom left cylinder would fire, and no others. then both cylinders on the left side. i could not figure out the issue so i decide to be a parts hanger, because all the parts are free. my other boat has the same identical engine that ran fine when i took it off the boat. the previous owner put on a new power pack two new coils and a new key switch before i got it. i changed the power pack, popped the flywheel from both motors and swapped the timer base assembly as a whole. the previous owner bought this motor off ebay from the guy who has sold over 500 motors with 99.5 % feedback. i checked compession it is at about 110- 115 all cylinders. it will start and run on two cylinders but obviously barely move the boat. the previous owner said it would only do 25 mph and i knew something was wrong with it but bought it anyway as he gave me another motor as well. so now i have 3 85 johnson's and can't get fire on this one. i really need some advice as to where to go from here. i swapped the orange coil wires on the power pack to the one that did not fire and it fired from that location so i have ruled out coils, power pack, timer base with sensor coils, and ignition switch. can any one tell me what i am missing. only the two cylinders on the right side will not fire.

 

[Solittle]

Re: fire frustrations

With parts from three engines you have a challenge. If you don't have one yet get the OMC shop/service manual specific to your engine and start methodical troubleshooting. I would stop swapping parts around and troubleshoot. As you go from one thing to another you will know what works. Keep at it until you find what dosen't then go to on to one the other engines for parts if you need them. It may be a simple as a loose wire or bad ground - troubleshooting will find it.

 

[roofcock]

Re: fire frustrations

both of the other engines ran. i have a seloc manual and a johnson manual both tell me to use this neon tester and push the button so on and so forth. the johnson dealers around here have no idea what this tool is. i have trouble shot what i can with out this tester and just started changing parts after that. i am very irritated with this. i may as well have changed motors for all this. the one that is on it has had a lot of freshening up so i wanted to use it. i went through the wiring harness and the previous owner had a bunch of splices so i pulled it all out and put on my newer style controls with an uncut harness. still have same issue.

 

[noelm]

Re: fire frustrations

I must agree with what has been said above, do not continue to swap bits back and forth, you will end up with a bucket of unknown good or bad parts, if the old wiring had been cut and joined, I would be thinking it is something quite simple, but will require a lot of mucking around to find it, as it stands, you may be chasing two or more faults that may have been introduced by all the swapping, use the genuine manual, (if it is indeed for your exact model) you can almost forget the Seloc one for this exercise.

 

[wavrider]

Re: fire frustrations

http://www.boatpartstore.com/tips.asp

http://www.boatpartstore.com/page40.asp

I have a 73 85hp, and went through the same problems.

the manual leaves alot to be desired with neon testers, talk about out dated.

the above links may help you in troubleshooting the system, it is a fairly simple system once it is understood.

 

[roofcock]

Re: fire frustrations

I must agree with what has been said above, do not continue to swap bits back and forth, you will end up with a bucket of unknown good or bad parts, if the old wiring had been cut and joined, I would be thinking it is something quite simple, but will require a lot of mucking around to find it, as it stands, you may be chasing two or more faults that may have been introduced by all the swapping, use the genuine manual, (if it is indeed for your exact model) you can almost forget the Seloc one for this exercise.

the parts i have been swapping are known good parts from one motor. the motor i have been taking parts from has a bent prop shaft but fires fine. the manual states no fire on two cylinders the cause is the power pack or the sensor coil...so i changed them both as well as the wiring harness for one with no splices

 

[roofcock]

Re: fire frustrations

so now i have removed everything from the other motor...stator timer base power pack and wire harness and gone through the wires looking for breaks frays etc. still no spark on cylinders 1 and 3. 2 and 4 fire like a champ. i moved coil leads and ruled out coils. someone has to of had an issue like this. help me please. this is driving me to my wits end as it is time consuming and the fish are hittin hard in the lake.
thanks
roofcock

 

[ezeke]

Re: fire frustrations

There is a grounding problem between the starboard cylinder head on this series of V4 engines which is partly corrected by a grounding strap running between the cylinder head and the rack that holds the ignition coils. At any rate, make sure that all of the wiring between the engine block and the various ignition components are cleaned. This is especially important in relationship to the spark plug wires and the spark plugs, and the ignition coils.

Are you testing for spark using a tester with all of the spark plugs removed and using a common engine ground?

 

[roofcock]

Re: fire frustrations

the grounding problem you speak of must be the issue. this was probably my biggest mistake of overlooking them and today i started to remove them and they appear to have a black coating on them i guess as a protectant... not sure? i will look into this further tomorrow afternoon when i get home from work and post back. yes i am using an automotive type spark tester and clipping the ground wire on the negative side of the starter solenoid gapping it about 1/2 inch with the plugs out. thank you very much for your thoughts and time. i will post my findings

 

[wavrider]

Re: fire frustrations

If you are getting 150v ac from the timer base to the amplifier, and not geting it out of the amplifier, it is the amplifier.

need a dva adapter or dva meter to read the peak ac output from your timer base.

there are two inputs from the timer base, one on the top of the amp and one on the bottom, you can try swapping them around to see if the spark will follow to #2 and #4,

if the spark follows to the other cylinders then it is a bad input to the amp as the amp switches the voltages.

if the spark remains on #1 and #3 and does not switch to #2 and #4 it is a bad amp

make sure all spark plug wires are disconnected if you switch the inputs around as the fire wil not be in time with the engine so DISCONNECT all spark plug wires before performing this test and it is always a good safety precaution to ground the spark plug leads so no stray spark will be running around,

Make sure all connections to the amp are connected as the amp needs the 2k ohm resistance from the coils to function correctly, if thee is no load on the coils then it is possible to damage the amp.

 

[roofcock]

Re: fire frustrations

is what you are calling the amp the power pack. i have not heard it called that so i am trying to verify we are on the same page
thanks

 

[ezeke]

Re: fire frustrations

It would be better to ground your spark tester directly to the engine block.

 

[roofcock]

Re: fire frustrations

first off to SOLITTLE you were dead on with something... so simple as the ground. and to EZEKE your explaination of the grounding issue with these engines turned my bull head the other way and made me look at it harder. it was the ground and i now have spark. i was so wrapped up in the idea it was something that created the spark being the issue (dirt bike 4wheeler experience) i overlooked the obvious and it wasted my time effort and patience. so to you both and everyone else that responded i send a big THANK YOU. i appreciate your help and opinions.

so, what i did that fixed the problem...

removed all grounding points on the starboard side, including both coils and power pack. using my angle head grinder(air powered little tool) with a wire brush wheel, i cleaned the ends of the ground wires and all mounting points to a new metal look. reattached everything and shazaam!!!! the caveman discovered fire. THANKS AGAIN.