72 seahorse starting issue

[FIRE34]

I have a 1972 johnson 20 H.P. Outboard. It has a problem starting. When i try and pull start the motor it does not do anything. But when I add gas into the carb, it fires up for a couple of seconds and dies. I just rebuilt the carb and replaced the points and condensers. Both cylinders have good spark, the fuel lines are all clear, new gas, fuel does pump through the fuel pump. Just dont know what else it could be Any help is appreciated.

 

[kbait]

Re: 72 seahorse starting issue

Symptoms = clogged carb. Remove the high speed jet plug from the carb bowl. If no fuel drains out, likely a stuck float valve (doesn't open when float is down). If fuel drains, likely a clogged main jet.

 

[tashasdaddy]

Re: 72 seahorse starting issue

you have spark, are the plug wire on the right plugs? are the plugs wet with fuel?
it really sounds like you either did not get the carbs completely clean, have not adjusted the slow speed needle correctly. also low compression can make one very hard to start. a rope start motor should have atleast 60 PSI on each cylinder, and be within 10 % of each other. most of your questions will be answered here, read it then repost here with questions. http://forums.iboats.com/showthread.php?t=299680

 

[FIRE34]

Re: 72 seahorse starting issue

I checkd to see if the bowl ahd fuel. And it did not, so I pulled the carb and removed the bowl. pulled the float and tried blowing air at low psi very little air flow. So blew it out with alot of psi and out flew a piece of what looked to be rubber or paper. reassembled and put back on motor. First pull it started and died after a second or two. after that no luck. So I am pulling carb AGAIN and am going to run through the whole thing. Any other tips are welcome. Also thanks for the ones I got

 

[FIRE34]

Re: 72 seahorse starting issue

Sorry forgot to add that I did have fuel on spark plugs. And incase you were wondering, thay are autolite plugs. I was just reading the forum about the whole NGK vs. Champion. Do you recommend me changin plugs? And yes plug wires are on the right cylinders.

 

[kbait]

Re: 72 seahorse starting issue

Since you found gunk, check the main jet for blockage. It's at the bottom of the carb bowl.

 

[FIRE34]

Re: 72 seahorse starting issue

I went through it three or four times after it not even starting at all. it did have a little bit of gunk once, but none after. after pulling off the hose from the pump to the carb, it looked a little torn up nside on the end. So i believe i found my source of gunk. Ill replace the hose sometime in my next thirty years and see if it runs. if not, Who wants to buy it??

 

[kbait]

Re: 72 seahorse starting issue

Ethanol fuel blends that they force on us nowadays reek havok on the inside of rubber fuel lines. Yours may be sloughing off and clogging your carb each time you clean it and pump more contaminated fuel in. You could try changing fuel lines from tank to carb, flushing it out before connecting to carb to be sure there's nothing left in the fuel pump. I'd think if you then connect to clean carb, it should work. I have a gas station in town that sells non-oxygenated fuel, and I've been using that for quite awhile to avoid the fuel line issue. I know it's frustrating, but since you've got it to fire for a few seconds, why not keep going?

 

[FIRE34]

Re: 72 seahorse starting issue

I know everyone hates the whole gas issues. Lucky you get the good stuff. lol. But I know the motor runs i was running around in the bay with it in the keys and it was fine at wot. But had an idle issue. So rebuillt the carb and changed the points and condensers because i did not know the history of the motor other than i traded my 9.9 for it to some rich guy so he could have less power on his yachts dingy. And i let this motor sit for a few years. And now im at where i am now. And im almost positive the carb is not tuned right. But I cant get it to run to tune it. Its turned out one and a quarter turns which is what ive read to start at. So idk what to do anymore im aggravated with the boat right now. it needs a new floor, fiberglass work on the hull, and paint. So i might just let it rot some more. get rid of it and continue with my jetski projects

 

[tashasdaddy]

Re: 72 seahorse starting issue

Ok. very good reading here, will answer a lot of your questions. http://forums.iboats.com/showthread.php?t=299680

have you check compression, i assume this is rope start, so you should have atleast 60 psi, and within 10% of each other. do you have bright spark that will jump 3/8 inch, using at spark tester? have you replaced the old fuel lines? did you remove and clean the high speed jet? behind the bowl drain plug. did you use a carb rebuild kit? did you do the basic low speed, carb adjustments?

we need to start at the beginning of the trouble shooting process, this is a very simple motor.

you are our eyes and ears, give us you best info.

 

[FIRE34]

Re: 72 seahorse starting issue

I need to get a spark tester to test that, but i know theres spark because i pulled a dont try this at home test. By putting a screwdriver in the boot and my brother pulled it to start and zap on both cylinders. Pretty strong.
I rebuilt the carb with a rebuild kit. Cleaned all ports and what not. put back on. It has a new fuel line from tank to fuel pump. Yes it is hard lined to the pump no connectors. But the line from the fuel pump to the bottom of the bowl on the carb is original. that is where i believe the rubber appearing in the carb is coming from. because it keeps showing up in the port from the fuel inlet to the carb and coming out of the float needle passage. After i clean the carb and put it on it will fire the first pull and run for a couple seconds and the die. I did this repeated steps.
I installed new points and condensors. Making sure the points were gapped to the specs. and that was that.
Replaced spark plugs with Autolite plugs.
And put fresh gas in the tank.

 

[ezeke]

Re: 72 seahorse starting issue

You don't say, but you have to use the choke on that motor and leave it on until the you can gradually let the choke out. The choke allows the pistons to pull a richer fuel/air mix by cutting off the air. Be sure that the choke plate is actually closing the throat of the carburetor.

 

[14ftgrumman]

Re: 72 seahorse starting issue

If you get to Wisconsin, I'll take it off your hands. Would make a nice addition to the 72 20 and 25. But I don't think my wife would agree with me.

Replace the fuel line from pump to carb. Remove carb and get the gunk out. Blow all passages out with compressed air. Set float level parrallel with the float bowl inverted.

 

[tashasdaddy]

Re: 72 seahorse starting issue

read the ethanol and carb cleaning, http://forums.iboats.com/showthread.php?t=299680 if the rubber is getting to the carb, it is clogging the high speed jets and may have clogged the pick up tubes going to the top 1/2 of the carb.

replace all fuel line is alcohol resistant lines. flush out lines before connecting to the carb.
again

 

[FIRE34]

Re: 72 seahorse starting issue

Yes the motor is choked when trying to start and stays choked until it sounds ready to be let loose. And yes the (butterfly) is closed and sarrounding the wall of the barrel. I will try and get the fuel line ASAP. But right now my dads in the hospital and he comes before the boat. And yes to cleaning it and what not.
And the line to the motor from tank is alcohol resistant so a couple bucks saved their yay.

Well if im ever in Wisconsin it looks like ill be having a little chat with your wife. lol. I would be glad to help someone with their I geuss you could say antiques collection.

 

[FIRE34]

Re: 72 seahorse starting issue

Ok well i changed the hose on the carb. went to start it and nothing. So this time now the bowl wont fill with fuel. Pulled the carb blewit out all ports are clear fluid runs through them, but when i go to prime it on the motor it wont fill. I used the hose to blow through tith carb off to see if float is seating and lifting properly and it seems to be. I just dont know what else to try. Its aggrevating me.

 

[F_R]

Re: 72 seahorse starting issue

Ok well i changed the hose on the carb. went to start it and nothing. So this time now the bowl wont fill with fuel. Pulled the carb blewit out all ports are clear fluid runs through them, but when i go to prime it on the motor it wont fill. I used the hose to blow through tith carb off to see if float is seating and lifting properly and it seems to be. I just dont know what else to try. Its aggrevating me.

It isn't exactly rocket science. If the fuel goes through the fuel pump and the hose to the carburetor when you squeeze the primer bulb, but won't fill the carburetor, there obviously is something preventing it from happening.

That something has to be the float or float valve. The float drops down, the float valve needle drops down, opening the hole in the float valve and gas flows in. When the bowl is full the float rises, shuts off the hole in the float valve, and gas stops flowing in till it needs more. Take another look. The problem should be obvious.

 

[FIRE34]

Re: 72 seahorse starting issue

Ok. so forget the whole not getting fuel to the carb. It was. good compression in both cylinders by the way. And good blue spark. Any other thoughts? Also what would be a good price to sell this motor at the point it is at now?

 

[FIRE34]

Re: 72 seahorse starting issue

Ok. So finally got it to run. I unscrewed the slowspeed needle almost three quarters of the way and tried just for the heck of it. And it ran i let it run on high idle for like ten seconds and tried to throttle down but it died. I throttled up and pulled and it started but same thing it died when i tried to throttle down. So i tried adjusting the needle moroe and had no luck. Now it wont start again. So im gonna pull the carb again to see if more junk came through but it shouldnt have because i replaced the line, and flushed all fuel compinents. Any ideas?

 

[tashasdaddy]

Re: 72 seahorse starting issue

it sound like the venturi on the low speed side are, clogged. they are on the engine side of the carb, up in the top of the carb barrel. very small holes. i have use a small paper clip to clear them. if not you will have to pull the core plug on top of the carb.