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1997 40 hp starts on starting fluid then dies

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Ken47374

Member
Installed a used powerhead, removed VRO and replaced with a fuel pump then installed dealer rebuilt carbs. Motor started with starting fluid, ran for about a minute. Now will start momentarily with starting fluid, but then no more. Disconnected fuel line going into the little plastic manifold that seperates and feeds the carbs and I had gas there under pressure.
Could you advise the next steps I should take to identify the problem?
Thanks for your help.
 
How old is your gas?
Is your gas contaminated?
Check your flywheel key.
Is there gas in carburetors?
Post compression numbers.
 
You appear to have a fuel supply problem.---Use primer bulb to fill carburetors.-----Then remove top carburetor drain plug.----Let fuel drain out till bowl is empty.------Now crank motor over with starter.-----Do you see fuel draining out of the top carburetor again ?
 
Gas is fresh.
I'm told, Compression is 150 in both cylinders.
I'm doing this by myself so I drained the top carburator into a folded t shirt. Then I moved the t shirt to a dry area and cranked the motor and the t shirt was wet about the same amount as when I originally drained it.
 
use 50-1 premix instead of starting fluid, the engine still needs the oil. Id look at your fuel lines, the vent could be blocked, inline filter could be clogged, if the fuel line could be creased somewhere.
 
We would like you to check compression and post numbers.
Ckeck flywheel key.
Check gas for contamination.
Is your choke/primer working on both cylinder?
Have you checked spark when it wont start.should jump open air gap of 7/16"
 
OK - got the compression checked before the rain came. Top cylinder is 135; bottom cylinder is 140.
I will resume checking as the weather clears.
Thanks for all of your good help.
 
To test the choke/primer can I simply disconnect the hoses from the carburators one at a time and push down on the key wilst turning it to turn the motor over and observe if gas is coming out of the disconnected hose? I am learning a lot about this motor thanks to you guys. Thanks again.
 
Ken47374 said:
To test the choke/primer can I simply disconnect the hoses from the carburators one at a time and push down on the key wilst turning it to turn the motor over and observe if gas is coming out of the disconnected hose? I am learning a lot about this motor thanks to you guys. Thanks again.
Click to expand...
That is correct.the primer works off of fuel pump pressure.
 
Wonderful - it runs. But it doesn't stay running.
I replaced the primer/choke with the one from the previous powerhead because I know it works. It still wouldn't start until I moved the red triangle on the primer/choke then I got a backfire. So I closed the red valve again and it started but died after a few seconds. I repeated the process and this time got back to the motor before it died. By moving the throttle I was able to keep it running at about 1200-1500 rpm's. But it still wouldn't stay running unless I kept goosing the throttle continuously.
Any thoughts would be greatly appreciated. Thanks.
 
Something is wrong with the carburetors , the adjustment or fuel supply.------Goosing the throttle is not an acceptable outboard procedure.
 
Thank you racerone. Can you tell me which adjustment to check. The carburators were rebuilt by South Central Marine before they were shipped to me. Thanks.
 
Roger that.
I have checked compression: 135 on top, 140 on bottom.
I will get a flywheel puller and check the key.
New gas with oil at 50/1.
Choke/primer feeding gas to both carburators. Yes, at least gas squirts out when I disconnect each line.
Don't know how to check spark for ability to jump open air gap of 7/16". Is there somewhere I can look to get a description of the test?
Also, local Johnson dealer was very ademant that I install a part # 435009 pulse limiter to avoid a fire in case of a backfire that would cause a catastrophe and burn the dock down. Could the pulse limiter be the source of any of my current problem with it not starting?
Thanks again.
 
No the PULSE LIMITER is a flow fuse !----It has nothing to do with starting / running of your motor.-----The pulse limiter closes should there be a pressure spike from the crankcase.------The large plastic components of a VRO pump could be damaged from high pressure.----Like they would crack / shatter !!!!-----And ask the local dealer or explain that the pulse limiter is NOT a flame arrester !-----They did not call it a " flame arrester " did they ?
 
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I believe the struggle is a continuing one.----There is just such a huge miss-understanding of how these simple motors work !!
 
fazbullet - yes it is, but it was a 40 hp powerhead that I was thinking about 50 hp carbs on. After reading your post I changed my order to 40 hp carbs, but I'm having trouble getting it running. Right now I'm working through the suggestions in post #7.
Like racerone says the struggle is a continuing one.
 
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