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1998 Johnson 115

wyatt Earp

New member
My 115 Johnson will run fine then after about 10 min it quits but will start back and idle for a min or two and quit again . Ideal it up same thing soon as I put in gear it shuts down any suggestions ?
 
First step is a compression test,run 3 times on each cylinder,carbs wide open,battery fully charged, follow that test with an open air gap spark test,third Fuel diagnostics,starting at tank,fuel pickup tube inside of tank,fuel/water separator,all fuel lines,filter,pump to carbs. for secure fittings, Primer bulb for firmness when pumped before startup. Is tank vent open and operational? check by removing fuel cap, Electronics have a tendancy to breakdown from heat after time,coils,stator,etc. A little more history on your engine would help, Is this a new problem? Ongoing issue? New boat to you? Old fuel in tank from last year? Is engine running at normal temperature? Ant warning lights or buzzers going off or on?
 
Is there a switch that makes the engine start on 2 or 3 cylinders, then when you throttle up, it engages the other 2 or 3 cylinders for normal operation? Assuming 4 or 6 cylinders.

My 1997 175HP V6 has this. I defeated the switch so now it starts on all 6 cylinders and runs with no issues.

I had a very similar issue as yours before I defeated the switch. Started out when I saw the switch and it looked really bad. I replaced it. Then had your issue. I defeated it by making it closed all the time.

Maybe this will help.

Dave
 
My J175EXEUE had this issue. My shop said they could fix it it but I could not see how so I defeated the switch. Has been working excellent for two years since ..
 
The only switch for this is the shift interrupter and bypassing it is hard on lower unit and cables.Its just a microswitch..There is no such switch on these models that makes it start on less cylinders and then kick in.
 
The easiest diagnostic would be to switch out to a 6 gallon portable tank and see if the problem disappears.
 
I have a 1998 90 hp which is I'm sure very similar V4. Often after starting, more than one person has said it sounds like not all cylinders are firing cleanly. Replaced elec ignition and carb rebuilt which fixed stalling issues at very low RPM , but still have this, I will call it auditory cosmetic issue as it doesn't seem to be an operational problem.
 
??----Put a timing light on cylinder #1 and start it up.-----Observe flashing light..---Repeat with 2 , 3 , 4 .-----May help to determine if a spark issue.----Or perhaps float bowls are warped.----
 
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