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1989 70hp hard to start when warm, why?

J

John Haggerty

Contributing Member
Motor starts fine after sitting overnight. It runs fine (10 miles), I shut it down and it is hard to start an hour later. Seems like it will only start without any giving it any throttle. Any throttle and I have to spin the starter to "dry it out". I find myself spinning the starter longer than I want to get it started.

Any ideas?

Thanks!
 
When you take the plugs out, check what colour they are too. If they are very black the motor may be running rich. This once gave me the exact symptoms you are describing.

Stuart
 
My 80's vintage Johnson 70 I had years ago was the best running engine I've ever had.. That engine started and ran even better than others I'd even bought brand new (including my fuel injected computer controlled Optimax's!).

I can't say what you have going on is normal, but with mine one of the most notable things was how it ran at low RPM and how it started. You never needed to use the choke or warm up lever - all it ever did was immediately start right up when you touched the key and then idled perfectly. If you used the choke or warm up it actually did not start so well, didn't want it.

Check the spark and plugs as mentioned, and look for other things going on, but the one I had liked to start with no choke at dead idle.

Jon
 
Out again today. Started no problem and ran 10 miles no problem. Fished 3 hours in the warm sun and again hard to start. Seems like its flooded. Eventually after working the started real good, it'll start. Runs fine then the same problem whenever it sits awhile. Short sits and it's fine.

Any ideas?
 
John Haggerty said:
Out again today. Started no problem and ran 10 miles no problem. Fished 3 hours in the warm sun and again hard to start. Seems like its flooded. Eventually after working the started real good, it'll start. Runs fine then the same problem whenever it sits awhile. Short sits and it's fine.

Any ideas?
Click to expand...

Did you ever find anything wrong with your motor, mine just started doing this the other day. Found my fuel hose deteriorating and plugged up the low speed jets on 2 of the carbs. Cleaned the carbs, replaced the hose and am still having the hard start after running then sitting for a bit.
 
Observe the stator under the flywheel closely (beginning of charging and ignition system). If it is dripping what looks like a sticky substance down on the timer base and powerhead area. that would cause a voltage drop to the powerpack capacitor, in turn resulting in weak, erratic, and eventually no ignition.

A stator in the first states of this meltdown may function perfectly when cold... BUT when hot, will not supply the spark needed for the engine to run.
 
For me (the OP) that problem went away. I feel it was two things that helped:
1) A carb removal, rebuild and replacement and switch to non-ethanol fuel.
2) New plugs and removal and replacement (using original wires) of all ignition related wires with a light abrasion of metallic surfaces and coating of dielectric grease.
Not sure what it was, but felt I couldn't go wrong cleaning both fuel and spark systems.
John
 
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