86 Johnson 175 missing

[Wayne65]

I purchased this boat a few months ago and it was running perfectly but started missing the last time out. What I believe started my problems was a Perkins switch was installed and the leads were reversed for a couple seconds. I have intermittent spark loss on several cylinders that I have been trying to track down and having no luck. I discovered it wasn’t charging and I had a weak battery probably from my stupid mistake so I replaced the regulator. I still had weak spark and replaced the stator. It is now charging and spark is good but intermittent on all but one cylinder and spark is still weak on one cylinder but it is firing. The engine changes when I pull the plug wire. The timer base was just replaced and no change but now the motor tries to keep running when I shut the key off. It doesn’t run well but sputters for 5-20 seconds until it dies. It didn’t do this until the timer base was replaced. Could the key switch or possibly a bad ground be causing this? Compression is 90 to 92 on all cylinders and fuel is not an issue. All parts replaced were new CDI parts. I tested the new timer base per the instructions and it is good. Does anyone have any suggestions?

 

[ct1762@gmail.com]

try swapping a good coil with the one that's intermittent after testing the coils resistance with a multimeter. takes 2 minutes. primary winding about .1-.2 ohms, and secondary 215-300 ohms (should read about 250). if nothing changes and since you did everything else, it must be the power pack. those go bad even when you have loose battery cables! if you have a good DVA meter ($20 on ebay) and the factory service manual, you can easily do all the test yourself, but the power pack is diagnosed through process of elimination. replace the pack as above.

 

[Wayne65]

Thank you for the reply. I ordered a power pack and will test the coils. Last night I cleaned all the plugs and all but one had oil dripping from them. I fired it up And it idled perfectly for about 5 minutes. I was getting excited and then like someone flipped a switch it shot out a poof of smoke and started missing. It almost seems like the VRO dumped a huge shot oil in the carbs. I’m going to disconnect the VRO and plug it off. Clean the plugs again and run it off a 50.1 mix to rule that theory out.

 

[Wayne65]

Update: I replaced the power pack and have strong spark everywhere but still have an issue It is firing on all cylinders but still has a slight occasional miss. The problem now is it’s not pumping water out the tell tale. I put a new water pump in and still no water. The old one wasn’t bad but I had it apart so I replaced the housing and impeller. It is installed correctly and pumps water when I spin the shaft but not when the motor is running. I put a hose to the tube going to the Powerhead and have water coming out of the tell tale but as soon as I start the motor it stops coming out. Is it possible there is an exhaust leak somehow putting pressure on the cooling system causing this issue. I’m totally out of ideas at this point. It was pumping water before the spark issue was fixed. This has me baffled. I was going to take it to be repaired but everyone is booked for weeks and I want to go fishing. The walleye are biting on Lake Erie.

 

[racerone]

Your compression numbers would be a concern to me.----Unless it has " low compression " thicker head gaskets.-----I am also surprised that the new powerpack did not fix your motor.-----Usually it fixes a host of issues !

 

[Wayne65]

The power pack fixed the intermittent and weak spark Issue and it’s definitely running better. It sounded like it was running on four cylinders before and idled very low RPMs. It is fast idling like it always has on muffs now. Since the compression is equal in all cylinders I’m not concerned. They were all tested with the throttle plates closed so I’m sure those numbers would go up if I opened the throttle. I just did a quick check on them because my first thought was I lost a cylinder.

 

[Wayne65]

I noticed the water tube going up to the Powerhead is very loose and originally thought it was normal but I just discovered it is leaking badly where it connects up inside. When I put the hose to it and shine a flashlight up inside I can see it gushing water. I got a nice cold shower doing this which my friend thought was funny. Looking at the manual it looks like the end is flared and has a rubber grommet at the powerhead. I’m guessing it’s not supposed to leak there. Does anyone know if the powerhead needs to come off to get to this and how big of a job am I looking at?