1986 85 hp

[pete j]

Last two times out my sweet running 85 went from sweet to super sour. I at first thought it was a carb problem but Ive replaced everything. so its not fuel delivery. Now Im thinking more towards in the line of an electrical problem. Motor starts off running great then just like I flipped a switch it starts dieing and it seems like its only running on 1 or 2 cylinders for a bit then I let off the throttle and idle slowly giving it throttle for a bit and the cylinders start firing again take off and same thing happens again and again. Yesterday after going out it just stopped running on all cylinders but got back to harbor. Ive been through carbs 3 times and seem clean as a whistle but Im at a loss now and I can not figure it out. I still dont know how to post pics but Im hoping somebody can tell from my explanation what the problem might be. Thanks for any and all help. forgot to say took cover off while on water to look at it an got the heck shocked out of me on the top cylinders spark plug wire but not on the lower 2

 

[Jiggz]

To make the troubleshooting easier (for fuel related problems anyways), install a clear fuel filter between the fuel pump outlet and the carbs inlet. Even a Fram G2 from Wally world for less than $5 will do. This is more for troubleshooting rather than fuel filtering . . . just make sure it is a clear fuel filter.

Thereafter, test the motor on muffs with the cowl cover off. Make sure it is full upright position. Prime the fuel bulb until firm and the clear fuel filter should be at least 3/4 full. Connect cooling water, place it in fast idle, engage choke and start motor.

As soon as it is warmed up, watch the clear fuel filter. Rev it up (using the carb tie bar) a little bit around 2000 ~ 2500 RPM in neutral and watch the clear fuel filter. Is it staying at least 3/4 or fully full? If it does you do not have fuel delivery problem. If it gets empty you have fuel delivery problem from the fuel pump all the way back to the fuel suction line, faulty fuel pump diaphragm, leaky fuel hoses, leaky primer bulb, etc.

Now if it would not start from the preceding steps, check for sparks and then compression on all cylinders. If both are good, then verify the flywheel key is not sheared. You do this by removing the #1 plug and inserting a long screwdriver and watch the highest point it will rise by manually turning on the flywheel. The highest point the screwdriver reaches should be the zero marking on the flywheel.

If this is satisfactory then do the fuel oil spray test. You do this by directly spraying fuel oil mix into each cylinder while cranking it over. If it starts will the fuel oil mix spray and the clear fuel filter is actually at least 3/4 full, then you have carburetion problem, i.e. too low of idle settings, air fuel idle setting is too low (should be around 1 ~ 1 1/2 turn out from lightly seated), or floats are stuck close.

 

[jerryjerry05]

Compression and spark test?
​The trigger wires on these motors are very thin and break under the shrink wrap.
Do a tug test on each of the trigger wires.
​I had an intermittent miss and found the trigger wires broken under the wrap.
​Get a spark tester $7-8
Post the results.
​Loss of spark could be stator, flywheel key sheared, bad trigger wires.

 

[pete j]

Thanks for the info Ive got fuel,water filters and everything else from reading all the other problems other people have. Its definity some kind of spark problem it runs great on the muffs and sometimes in the water so flywheel ,stator check starting today, wish me luck when it loses spark the plugs foul and it messes up a whole day of fun with shocking results.

 

[Jiggz]

If plugs are fouling, check the idle fuel air mixture screw settings. It should be around 1 ~ 1 1/2 turn out from lightly seated. Make sure fuel oil mix is 50:1.

 

[pete j]

oil mix is good,but before I took the motor apart I thought I d take a look behind the plate that holds the coils. saw some crust on all of the ground wires on the coils, started cleaning them up and the ground wire to the center coil fell of the ground point, finished cleaning them all up put new connector on bolted it back up, fired it up and it was purring like a kitten. just to check I shut the motor down and put fouled plugs in the motor fired it up and it took a second but all the plugs were purring too. dont know how important a ground wire on a coil is but it sure seems like that was my problem. my idle screws are 1 1/8th out. Thanks for all the help and hopefully that is my problem

 

[Nordin]

Nice to hear you may have found the issue.
I just want to clarify that the grounding are very important to the ign.system.
Most CDI, ign.coil etc need the ground for voltage reference. Some components in the system do not need/should not have connection to ground such as triggercoils.

A wire diagram is needed when troubleshooting ignition systems.

 

[pete j]

Ive got a manual with the diagram and I will know for sure if I found the problem tomorrow . thanks for the great info

 

[pete j]

Well its sad news for me and back to the drawing board. Boat ran great all day then as I decided to come in the boat did the same thing, as Im moving fast thru the water it just started missing again, so the fly wheels coming off to check wires on stator and what ever else I can find