84 Johnstartson 60 hp strted and ran good then went downhill

[lmbr]

Motor started and ran good for 5 min then started missing. Ran good intermittantly finished barely running at full throttle. Will start and run so so in neutral with warm up lever. Just filled up prior to using. Have replaced fuel pump and fuel line and bulb. Rebuilt carbs a couple of months ago.

 

[fishfeatures]

Re: 84 Johnstartson 60 hp strted and ran good then went downhill

check to see if all cylinders are getting spark , use a open gap spark tester set to 7/16 i think

 

[lmbr]

Re: 84 Johnstartson 60 hp strted and ran good then went downhill

check to see if all cylinders are getting spark , use a open gap spark tester set to 7/16 i think

I'm not sure what an "open gap spark plug tester" is. I am about to leave and be gone for the weekend so I will not be able to check for spark until Monday.

 

[boobie]

Re: 84 Johnstartson 60 hp strted and ran good then went downhill

You can buy the open air gap tester at any parts house for around $8.00.

 

[LongLine]

Re: 84 Johnstartson 60 hp strted and ran good then went downhill

Make sure you didn't get some "garbage" gas.

 

[lmbr]

Re: 84 Johnstartson 60 hp strted and ran good then went downhill

Make sure you didn't get some "garbage" gas.

That's what I have been concerned about. Guess I will dump the tank, start over and see what that does. Meanwhile I will also see if I can get an open gap spark plug tester. Hope it comes with instructions since I'm not familar with one of them.

 

[lmbr]

Re: 84 Johnstartson 60 hp strted and ran good then went downhill

New update. I got a spark tester and when I started the engine to test the spark I found that fuel is leaking pretty significantly from the lower carb. I removed both carbs and opened them to check for float adjustment and to be sure the needle valve were OK. Did not find a problem. Haven't finished reinstalling them. I did watch the spark tester on both cylinders. One appeared good. Couldn't tell for sure on the other. I might be safer to just go ahead and replace both coils? I think that requires pulling the flywheel? If so, what is the best way to do that?

 

[lmbr]

Re: 84 Johnstartson 60 hp strted and ran good then went downhill

Fixed carb leak. Engine runs OK now but still has a slight studder. I have ordered 2 new coils and after reading the repair manual see that te coils are located next to the spark plugs. Also ordered the 3 tools to replace the wires in the waterproof plugs. Hope this will finally give me a smooth running motor. I have previously checked the compression in both cilinders and they are both OK. Anyone have any other suggestions?

 

[fishfeatures]

Re: 84 Johnstartson 60 hp strted and ran good then went downhill

first thing , don't start throwing parts at the motor , find the issue then sort that out. What happens if your new parts don't sort your studder ?? you're still going to be in the same place.

hope they do sort it if not post back.

 

[lmbr]

Re: 84 Johnstartson 60 hp strted and ran good then went downhill

first thing , don't start throwing parts at the motor , find the issue then sort that out. What happens if your new parts don't sort your studder ?? you're still going to be in the same place.

hope they do sort it if not post back.

Don't think I am throwing parts at the motor. I did check the spark and found one was very weak. This is an 84 Johnson and both coils appear to be original equipment so I made the decision to replace them both. If they are not the whole problem then at least I will know they shouldn't give me a problem later.

 

[LongLine]

Re: 84 Johnstartson 60 hp strted and ran good then went downhill

Make sure your interconnecting gas hoses/connections are tight & in good shape. I found with my 75 hp (actually my mechanic friend found it as it was driving me nuts) that when the air silencer was put back on, one of the elbows leaked.

As for the coils,as long as you could afford them, it was good that you changed them. If one was truely weak then it would have given out enventually. Kind of a Preventive Maint thing.

 

[lmbr]

Re: 84 Johnstartson 60 hp strted and ran good then went downhill

I did check all the fuel lines and carbs. I readjusted the gaskets on the bowls of both carbs and then replaced all the connecters on the fuel lines starting with the connector on the new fuel hose at the motor and all the way to both carbs. I had a leak before I did that but that cured it. The motor starts and runs good now but it seems to have a very slight studder so after finding the spark weak, I'd rather be safe than sorry. I ran out of gas 4 miles from the launch ramp on a less traveled lake during mid week a couple of months ago. Not fun, so I want to be sure that whenever I turn the key it is going to start and run until I get back. $60 for 2 coils is cheap compared to being stranded on a lake. I haven't learned to "walk on water" yet.