Johnson 20HP extremely high compression wont start

[justinbill]

i have a 20r73a with electric start. i was fixing an electrical problem and got the motor to start a couple of times for 3 or 4 seconds but all of a sudden it got extreamly hard to pull, electric start can turn flywheel fast enough yo start. any ides what it could be turns fine without sparkplugs.

 

[tashasdaddy]

Re: Johnson 20HP extremely high compression wont start

engine is freezing up, do to lack of lubrication. or

90% of starter problems are bad connections. remove and clean both ends of the battery cables, so that they are shiney, also the cable from the solenoid to starter. check for nicks in the cables. and make sure the connectors are on the wire good. the cable tend to corrode from the inside out, if nicked, corroded wires, and connections, heat up and cause resistance to the follow of electricity, thus the starter doesn't get enough. you can also take jumper cable pos battery post to large post on starter. with a good connection, the engine should spin. then if the starter is good clean everything and retest. then trouble shoot solenoid. starters can be rebuit at a starter/alternator shop, much cheaper than a new one.

also have the battery load tested at the auto parts store, free, i've had new batteries go bad

 

[justinbill]

Re: Johnson 20HP extremely high compression wont start

i bet its lubrication problem. it feels the same with the pull start. any tips on the best way to lubricate it back to health.

 

[jbjennings]

Re: Johnson 20HP extremely high compression wont start

Try spraying a little lightweight oil in the spark plug holes and spray some through the carb. throat as well. Then, pull it over a few times to blow it out the exhaust ports after it's soaked for a few minutes.
Have you been trying to start it with straight gas through the carb throat?
I find it odd that it turns over fine with the plugs out.
Something odd is going on for sure.
JBJ

 

[noelm]

Re: Johnson 20HP extremely high compression wont start

you do have oil in the fuel don't you?

 

[justinbill]

Re: Johnson 20HP extremely high compression wont start

Yea their is oil in the fuel, it was running right befor this happend. I was cranking it with the electric start, it started i turned it off tryed to crank it up after that it will not turn easily. its like the compression has increased by 100% it turns over but its really hard. when the spark plugs are out it turns fine. could it be exaust.

 

[lindy46]

Re: Johnson 20HP extremely high compression wont start

Lower unit problems? Try dropping the lower unit and see if it cranks any better.

 

[R.Johnson]

Re: Johnson 20HP extremely high compression wont start

Are you cranking, or running this engine in the water? If so, with the plug's out. Crank it over to see if there is any water in the cylinder, or cylinder's.

 

[steelespike]

Re: Johnson 20HP extremely high compression wont start

Are you cranking, or running this engine in the water? If so, with the plug's out. Crank it over to see if there is any water in the cylinder, or cylinder's.

Yes could be water in the cylinders.If it has been running that way for any reasonably long time one plug may be extremely clean.It may also make a lot of steam( disperses faster than typical smoke)

 

[justinbill]

Re: Johnson 20HP extremely high compression wont start

no it not in the water. i dont see any water in the cylinders.

 

[justinbill]

Re: Johnson 20HP extremely high compression wont start

i dropped the lower unit, but its still hard to turn. i really appreciate all the help. keep the ideas comming.

 

[cheesegrits]

Re: Johnson 20HP extremely high compression wont start

Do you have muffs on it hooked to a waterhose?

 

[justinbill]

Re: Johnson 20HP extremely high compression wont start

yes i have a water hose hooked to it.

 

[Whoopbass]

Re: Johnson 20HP extremely high compression wont start

I have a 15 hp Force with a bad coil that is a prick to start. It's hard to pull and it rips the rope out of my hand half the time when it recoils.
I haven't fixed it yet but I think the bad coil is causing the problem even though it doesn't make any sense to me.

 

[R.Johnson]

Re: Johnson 20HP extremely high compression wont start

I'm at a loss here! Are you turning that engine over with the electric starter, or the rope starter? To me, and the way you discribe it, it sound's like the engine is hydro locking. That mean's the cylinder is full of liquid, water or gas. You are trying to run the engine out of water, so that leave's gas. Take the fuel pump off what ever cylinder it is hooked to and crank it over. At this point you are jumping from a hydro locked engine, to a bad electric starter, to a bad electrical connection. Say what you are doing, and how. Electric starter, rope starter, plug's in, plug's out.

 

[justinbill]

Re: Johnson 20HP extremely high compression wont start

ok sorry for the confusion, if i use the electric starter it does not have enough torq to turn the engine over, if i use the pull start it is extreamly hard to pull with the plugs in. if i take the plugs out it turns fine on the electric starter and the pull rope.

 

[bustermin]

Re: Johnson 20HP extremely high compression wont start

How many volts do you have at the starter while cranking? Have you checked to see what the compression is for each cylinder? Also, you could try removing all the plugs except one, and then try to start it. If it turns add another plug, keep doing this till it won?t turn. Doing this may help you determine which cylinder is the problem.

 

[justinbill]

Re: Johnson 20HP extremely high compression wont start

ok its not a starter problem cause it does the same with the pull rope. i tried to take one spark plug out and it turns fine. i put it back in took the other one out it turns fine. if i put them both in thats when it has the problem.

 

[bustermin]

Re: Johnson 20HP extremely high compression wont start

did you check the compression for each cylinder?

 

[justinbill]

Re: Johnson 20HP extremely high compression wont start

how do you do that, im pretty new at this