johnson 90hp have to pump bulb

gahunter706

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I have a 2006 johnson 90hp that I have to keep the bulb pumped for it to get on plane and get it up to full speed. It started doing this a couple of weeks ago, but wasn't nearly as bad then, and it has gotten progressively worse since. When I give it throttle, it will start to go and then once I hit a certain RPM it will just bog down like it is starved for fuel (which I'm pretty sure it is) if I give it any more throttle. If I have someone sit there and pump the bulb it runs great as it should. I put a new bulb, line and tank fitting on it last night, as well as bypassed the water/fuel separator and it ran no differently. I have looked over the whole motor multiple times, and I don't see gas leaking from anywhere and the bulb gets hard when the motor isn't running, like it should. I am thinking the diaphragm in the VRO pump might be torn and that it needs to be rebuilt, does this sound like it could be my issue? Any advice or other things to check would be greatly appreciated. Thanks.
 

ondarvr

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Check the fuel pump (as you suspected) and also look for an air leak, it can be either one. O-rings in the fuel line connectors can leak under vacuum but not under pressure when the bulb is squeezed.
 

gahunter706

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Well I rebuilt the fuel pump, although when I took it apart there looked to be nothing wrong with the diaphragms. I also sanded the carb bowls down flat because they were warped and leaking a little bit of fuel. Took the boat out on the water and it runs great on the top end, but it will not idle at all. I have to start it and get it in gear before it shuts off because it will not idle more than 3-4 seconds. Also, it runs rough until it gets to about 2000 rpm, then it takes off and runs as it should. Any ideas what this could be? I guess I will take the carbs back apart and make sure they are clean, although they looked fine when I put them back on.
 

gahunter706

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Just finished cleaning and rebuilding the carbs and this motor still wont idle. If i push in the key (priming it) before it shuts off, i can keep it going for a little longer. And as i said above, it runs very rough at low rpms. Any ideas what my problem could be?
 

jakedaawg

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Compression test,

Does it idle if you squeeze the bulb?

Run 50:1 Mix until this is sorted out.
 

Silvertip

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The problem started after you fussed with rhe carbs. Therein lies the problem.
 

racerone

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Post the results of a compression test.------Do you have spark that will jump a gap of 3/8" or more, yes or no ??
 

gahunter706

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I finally got a chance to look at the motor yesterday. Compression is good and it has good, strong spark. I thought the problem was a lack of fuel, which is why I had to keep priming it to keep it running at idle. But I took it to the lake yesterday and couldn't get it to start because it flooded itself bad enough that there was gas coming out of the front of the carbs. Fished for a couple hours and tried to start it again, same thing.
 

racerone

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Test run with a known to be good tank and hose.-----What is " good " compression and spark ??----See post # 9-----Is the starter / battery in good condition ?
 

gahunter706

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I run another outboard (9.8 tohatsu kicker) off of the same tank and have had no issues with it, so I dont think the tank is the problem. Fuel line and bulb are brand new. Compression was 120-130 on all cylinders and spark jumped a 1/2" gap on each cylinder. Yes, starter and battery are both in good condition.
 

82rude

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Ive actually had the fuel line fitting at the motor fail.The one you plug your hose into.It can give you intermittent issues
 

jakedaawg

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If there was gas coming out of carbs you have a float/needle/seat issue. Only way that happens.
 

gahunter706

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I put new floats, seats and needles in the carbs when i rebuilt them. What is the proper way to set the float height?
 

gahunter706

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Thats what i thought, and that is how i set them. Any other reason the needle wouldnt be seating properly?
 

jakedaawg

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Heavy float/bad leaky float....missing washer gasket under seat if applicable ( can't remember on that model)...poor installation.

With the engine tilted ever so slightly, just enough to get a forward slant on carb throats squeeze the bulb till its hard, then continue to squeeze gentlly. Eventually you will flood the carb/s that are culprit. Pull those apart and inspect/reinstall floats and seats.

On some models of carb you could even get the floats installed upside down but I do not believe that is the case with this motor.
 

gahunter706

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Heavy float/bad leaky float....missing washer gasket under seat if applicable ( can't remember on that model)...poor installation.

With the engine tilted ever so slightly, just enough to get a forward slant on carb throats squeeze the bulb till its hard, then continue to squeeze gentlly. Eventually you will flood the carb/s that are culprit. Pull those apart and inspect/reinstall floats and seats.

On some models of carb you could even get the floats installed upside down but I do not believe that is the case with this motor.

You were right, once the carbs filled up gas was coming out of the throat of the top starboard carb nearly as fast as i could pump it in. I ended up taking the boat to a shop to get looked at because i just havent had the time to work on it lately.
 

jakedaawg

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You were right, once the carbs filled up gas was coming out of the throat of the top starboard carb nearly as fast as i could pump it in. I ended up taking the boat to a shop to get looked at because i just havent had the time to work on it lately.

Sometimes thats the quickest, easiest, and in the long run, cheapest way to go.
 
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