I am STUMPED! please HELP!

[chiefcatchemall]

Hello all, this winter I bought a 1973 seahorse johnson 20 HP. Model #20R73A. The most I have have had it tunning for was about 1 minute. It usually is only about for 5 seconds. I get a little smoke as well. I use 50:1 fuel/oil ratio. I am honestly stumped. Being an older outboard, and in good shape I thought I would do a bit of work on it and have myself a reliable motor. It only ran for a lttle while when I first brought it home. Again for only about 3-5 seconds. That is WHEN i could get it to fire. I wasnt getting good spark when I first got it but did replace all electrical. Here is a list of what I have done to it so far...



-Replaced, the points and condensers. Set points to .020.
-Replaced the primary ignition coil underneath the flywheel
-Replaced the exterior coils
-replaced my water pump
-changed lower unit oil
-rebuilt my carb, blew out all opening w/ compressed air. (set float parallel with bottom of carb bowl)
-rebuilt my fuel pump, following step by step instructions
-took head off and cleaned the piston crowns so they were good and clean. (FILTHY IN THERE!) Also the cylinder walls were in great shape, no dings, or scrapes. I put a few drops of 2 stroke oil on my finger and lubed up the cyls.
-Torqued head bolts to correct spec
-New spark plugs.
-Recoil spring was busted, so I fixed that
-also not that this matters, but I replaced the kill switch because that was shot


This is everything I have done to it. The plugs are getting fuel, I have good spark, and compression...I am lost:facepalm: I know there are a lot of guys here that are very knowledgeable and are expert machanics on these things. I am lost guys....

 

[mxcobra]

Re: I am STUMPED! please HELP!

i had to use a drill to turn mine fastest enough to start
fuel/air spark and compresion is what you need to run?
How about the timing?

 

[chiefcatchemall]

Re: I am STUMPED! please HELP!

Not sure about the whole timing thing...I do get a loud backfire pop when trying to get it to fire. It happens about once every 10 pulls or so

 

[bonzoscott]

Re: I am STUMPED! please HELP!

There are probably others on here that could give you better direction, but if were me: 1st - Use adjustable spark gap tester and make sure you are getting spark at 1/4 inch gap. 2nd - Make sure your fuel pump is working. Disconnect the rubber line from the pump to the carb and crank the motor. There should be good pulses of fuel coming from the line. 3rd - If it still doesn't run after that, you probably need to go through the carb again. Been there-done that. I was successful only after soaking the carb body in SeaFoam for a week, then air compressor to it real good. Hope this helps. Oh yeah! probably 1st and foremost - make sure your tank, fuel line, and filter in the pump are clean....

 

[Haffiman]

Re: I am STUMPED! please HELP!

Not sure about the whole timing thing...I do get a loud backfire pop when trying to get it to fire. It happens about once every 10 pulls or so

Mixed up the plug cables or a broken flywheel key??
When putting back the flywheel, clean cone on crank and in flywheel with thinner/aceton and torque to specs!!

 

[chiefcatchemall]

Re: I am STUMPED! please HELP!

Carbs been soaked and blown out wih compressed air. Fuel pump is together right, I am getting fuel to plugs. Getting spark to jump well over 1/4 inch. Plug cables are deff on right...The flywheel key isnt broken. Has a few small scrapes in it. Flywheel was torqued to 40 ft/lbs.

 

[tx1961whaler]

Re: I am STUMPED! please HELP!

The backfire (through the exhaust ??) would indicate that the timing was off. About the only thing that affects that is the points, flywheel key, and coil/plug wiring. You can try and reverse the plug leads for fun. It won't hurt anything.

 

[mxcobra]

Re: I am STUMPED! please HELP!

Not sure about the whole timing thing...I do get a loud backfire pop when trying to get it to fire. It happens about once every 10 pulls or so

yes and yes this happens when timing is off!
find and fix this problem and you will have a great motor
by the way i really like theese motors power to wight ratio is good i put a 35 hp carb on mine and she really came to life

 

[mxcobra]

Re: I am STUMPED! please HELP!

spray a quick shot of starting fluied doun the carb if it dose not fire this way you will know for sure you have a spark timing isue..
I have heard of flwheals being droped and switching polairady dont know if its true or not

 

[kfa4303]

Re: I am STUMPED! please HELP!

WRONG, WRONG, WRONG Mxcobra. NEVER, EVER spray carb cleaner, or starting fluid into a 2-stoke engine as it will strip the innards of much needed lubrication. Furthermore, the timing is automatically set on these motors through proper placement and alignment of the flywheel and otherwise does not need to be "set". Unfortunately, Chiefcatchemall you have one of the early 70's model Johnsons that started using the new, "improved" ignition systems rather than the much loved and dead simple OMC "universal" magneto system. While I'm not personally a very familiar, or much of a fan of these systems there is hope. You should still be able to convert your set up back to the simpler magneto system used in previous models, which may be the best solution in the end. Here are some links that can walk you through both your "improved" ignition as well as the old magneto systems. Good luck. Keep us posted.

http://www.sschapterpsa.com/ramblings/johnson_9.9_magneto.htm

http://www.duckworksmagazine.com/03/r/columns/max/07/index.htm

 

[chiefcatchemall]

Re: I am STUMPED! please HELP!

Yes I will not be spraying carb cleaner in it at all...I read the fist article and found this part to be interesting...


The point contacts seldom wear out, but it is the phenolic rub bar that activates the points that rubs on the timing cam that does wear. When it does the points gap becomes closer, changing things dramatically. There is a felt wick that lubricates this rub bar. It needs to be lubricated. For this I like to use a tad bit of the old Power Surge or reloading case lube. This is sticky enough to not get thrown off during the running & a little bit goes a long ways.

 

[chiefcatchemall]

Re: I am STUMPED! please HELP!

Also, I am going to try to avoid switching back to the older style system. The only reason is I just replaced all 3 coils!!! Wish I didnt however...Good stuff guys thanks. Might go tinker with it a bit more here in a little while..

 

[chiefcatchemall]

Re: I am STUMPED! please HELP!

The backfire (through the exhaust ??) would indicate that the timing was off. About the only thing that affects that is the points, flywheel key, and coil/plug wiring. You can try and reverse the plug leads for fun. It won't hurt anything.

Yes the backfire pop is through the exhaust. Going to go back in and take a look at the points and see if all is good.

 

[chiefcatchemall]

Re: I am STUMPED! please HELP!

Well guys I got it running. Not smoothly though. I need to keep it at wide open throttle to keep it running. Also it sounds like its skipping. itll run for 3 seconds make a couple pops then go back to running and just keep repeating that. As soon as I back off the throttle it wants to die. Any ideas guys? I am kind of happy of where I am with it right now, seeming how I could only get it running for about 3 seconds at a time beforehand...I was playing with the slow speed needle but didnt seem to help much...

 

[chiefcatchemall]

Re: I am STUMPED! please HELP!

Just pulled the plugs and they are BLACK!!! Brand new ones. Ran it for a little bit in a trash can once i got it running...Just the other day I did a decarb...took the head off and cleaned the piston crowns so they were nice and clean...so I know its not that...What would cause this? too much fuel to the plugs? My ratio is 50:1 so I know its not my mixture...

 

[64osby]

Re: I am STUMPED! please HELP!

Black plugs mean too rich. Sounds like you might need to revisit your carb.

Before you do that you might want to do a compression test if you haven't. You didn't post any numbers if you did.

 

[chiefcatchemall]

Re: I am STUMPED! please HELP!

I just tore carb down. made sure float level was good and blew everything out!!! 110 & 108 on cyls...LOST:facepalm:

 

[coolbri70]

Re: I am STUMPED! please HELP!

check the float needle valve if it does not seat good fuel can leak past causing these symptoms wot helps clear the fuel then when you let off the airflow it floods out and dies

 

[kfa4303]

Re: I am STUMPED! please HELP!

This link will help you dial in the carb. Make sure your spark is jumping a 1/4" gap too. The compression sounds great, which is the most important thing.

http://forums.iboats.com/showthread.php?t=167352

 

[Haffiman]

Re: I am STUMPED! please HELP!

Mark up your flywheel with TDC on both cylinders, hook up a timing light and check roughly the timing. With throttle in idle position, it should be around TDC.