1988 90hp Johnson QUITS RUNNING

montauk1

Seaman Apprentice
Joined
Nov 13, 2010
Messages
31
Hi

1988 Johnson 90hp (vro by passed).

Has a little problem starting at the ramp, once at idle runs great! Getting outside the Harbor I start to excelarate to faster RPM's runs good for about 3-5 minutes and then engine sounds like it is running out of gas and dies. Then it is really hard to get started. have to let it sit for some minutes. Keeps repeating symptoms. New Plugs, New fuel pump (do to bypass VRO) Rebult carbs. I did notice that the starboard plugs were some what dry and the port were very wet.

Can anybody help

Thanks
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: 1988 90hp Johnson QUITS RUNNING

Have you checked your ignition yet to see if it will jump a 7/16 " open air gap?
 

montauk1

Seaman Apprentice
Joined
Nov 13, 2010
Messages
31
Re: 1988 90hp Johnson QUITS RUNNING

boobie, Hi,

How do you check you ignition to see if it will jump a 7/16 open air gap?
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: 1988 90hp Johnson QUITS RUNNING

Go to any parts house and get an open air gap adjustable spark tester for around $10.00. Set it for 7/16 " and check your spark on each cyl. Should show a nice blue spark on each cyl.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: 1988 90hp Johnson QUITS RUNNING

Wet plugs can be an indication they are not firing. An inductive timing light is another common/good tool which will show the condition of spark on all 4 wires.
 

montauk1

Seaman Apprentice
Joined
Nov 13, 2010
Messages
31
Re: 1988 90hp Johnson QUITS RUNNING

Ok so all four jump a 7/16 gap, also did a compression test, 124 on all four. also took apart my carbs to check for any clogged orfices or jets, found a small piece of dirt or plastic in one,Could that couse the bog? Carbs were rebuilt a month ago no sticking floats or anything. What about water in the gas tank? Would that couse a bog and quit? or would that just make it sputter.
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: 1988 90hp Johnson QUITS RUNNING

You may want borrow a 6 gal tank and hose and try it. This eliminates the boat fuel system.
 

montauk1

Seaman Apprentice
Joined
Nov 13, 2010
Messages
31
Re: 1988 90hp Johnson QUITS RUNNING

I found a good amount of water in the bowl of my carbs, also found good amont of water in my fuel tank, on top of finding one clogged injector (small piece of plastic) could this all cause engine to bog and die at higher RPM?
 

blimp

Petty Officer 1st Class
Joined
Sep 30, 2009
Messages
237
Re: 1988 90hp Johnson QUITS RUNNING

I think i had the same issue last week. My fuel/water separater was full of water and I was having the same symptoms. I have drained my tank, but i think there is still some water in there. I am going to pull the tank out and drain it completely while using smaller external tanks to run the engine.
 

waynehol

Petty Officer 3rd Class
Joined
Jun 4, 2009
Messages
88
Re: 1988 90hp Johnson QUITS RUNNING

I found a good amount of water in the bowl of my carbs, also found good amont of water in my fuel tank, on top of finding one clogged injector (small piece of plastic) could this all cause engine to bog and die at higher RPM?

Yes, the small piece of plastic in the clogged injector was probably the high speed, thus the loss power and sounds like the water is the problem for starting

Just my .02
 

montauk1

Seaman Apprentice
Joined
Nov 13, 2010
Messages
31
Re: 1988 90hp Johnson QUITS RUNNING

Just drained out about 15 gallons of gas out of my tank, got to the last 3 or so gallons and trapped a whole cup or more of water in a glass jar. that has to be the problem with the WOT bog then die issue. T
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: 1988 90hp Johnson QUITS RUNNING

"One clogged injector" ?????????????
 
Top