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1999 175 hp Johnson troubles

J

jbass

Member
:confused: Have a 1999 175 hp Johnson solid motor but having strange issues.Cranks and idles fine on cold starts,runs fine wide open,throttle down from wide open to idle (does fine) shut down and let sit for MORE than 10 minute.,,spits ,sputters and cuts off (will not idle without dying out) unless I throttle up asap,,then runs fine at wide open again. Have replaced VRO/Fuel pump/checked primer selonoid/checked primer fittings and hoses for stoppages/replace priming ball/replaced fuel lines,,,still same issue.,,,,,I NEED HELP<does anyone know where to look next?????
 
Does pumping up the fuel primer bulb "hard" before each start up make any difference, and if so, in what manner?
 
I have been told that my cooling system may be on the brink of overheating and causing the gas to evaporate. does this make sense?
 
Put a timing light on the plugs ( one at a time ) and see what happens when it acts up.---------------------Will help you decide if it is fuel or ignition related.---------------------Trouble shooting is the way to go , throwing parts at it will cost a lot of money.
 
runs fine wot and idles fine at throttle down,,,can idle all day,just as long as I don't shut down from more that 10 minutes and try to start up spits and sputters
 
Are you saying you don't want to / don't need to trouble shoot ??----------------------How long have you owned this motor ??
 
Did not mean that,,, at this point I have troubleshooted all that I know to do, just looking for new direction. I am overlooking something simple probally

have had the boat 10 years (taken care of)
 
Under the flywheel is the stator which is the beginning of both the charging and ignition system. There are a series of small coils that pertain to the charging system.... and at the rear portion of the stator are two larger enclosed black coils that provide approximately 300 AC volts to the powerpack which is needed to energize the ignition system.

Unfortunately that stator runs extremely hot, and eventually causes one or both of those black coils to melt down. When this happens, a voltage drop takes place which results in weak, erratic, and eventually no ignition. Normally this melt down of those black coils starts out by still providing the proper voltage to the powerpack when it is cool, and only affects the ignition when the stator becomes hot.... but eventually it fails altogether, just a matter of time.

So inspect those stator black coils visually and closely. If you see a sticky looking substance dripping down from either of them upon the powerhead area, replace it.

Let us know what you find.
 
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thanks for the info,will check these coils out,,,is interesting because I replace a bad powerpack some months back around the time this started,,will let you know what i find
 
The 2 coils are part of the stator.------------------Anything dripping off them would be clearly visible on the block.
 
I'm not knowledgeable of the 1999 V6 flywheel and/or its possible guard/cover design, therefore I don't know if you would need to remove the flywheel or not. On the older models, all one had to do is look closely under the flywheel, using a good flashlight.

As Racerone states, that melt down dripping should be visible on the block.
 
checked powerhead this weekend and saw no evidence of dripping/melting coil. Troubleshot primer seloid and key switch for uncontroled priming at start up also. Checked cooling system for blockage /checked recir line (one side,,that I could get to) what would you suggest to troubleshoot next,,
 
I gather that pumping the fuel primer bulb before each start up sequence has a tendency to correct the problem temporarily. If so, that indicates that when the engine is shut down for a fishing period or whatever, the fuel within the lines may be draining back into the tank. This could take place if the "anti siphon" valve is stuck open or is missing altogether. Normally the anti siphon valve, when faulty, sticks in the shut position and results in a fuel restriction but the opposite occurs from time to time.

If the fuel is draining back into the tank, that leaves no fuel or very little fuel at the VRO pump, BUT the oil section of the VRO is in full operating order. Starting the engine and running it on what is left in the carburetors etc results in having the VRO pump excessive oil to the carburetors. This would of course result in a bad running engine.

Replacing a portion of the fuel line with plastic hose would allow you to see if this backwards fuel flow is taking place, but do check the anti siphon valve. I realize you're not checking it for a fuel restriction as described below, but check to be sure that it is present in the fuel system and not stuck in the open position.

(Fuel Anti Siphon Valve)
(J. Reeves)

Many of the later OMC V/6 engines incorporate a fuel restriction warning via a vacuum device attached to the powerhead. If the engine overheats, or if you have a fuel restriction, the warning is the same.... a steady constant beep.

NOTE... Only the V/6 & V/8 engines have the above "Fuel Restriction Warning". The warning horn will not sound on the other models.

The fact that a engine is not overheating, but the warning horn sounds off with a constant steady beep, and that the rpms drop drastically would indicate that the engine is starving for fuel due to a fuel restriction. Check the built in fuel tank where the rubber fuel line attaches to the tank fitting. That fitting is in all probability a "Anti Siphon" valve which is notorious for sticking in a semi closed position. It will be aluminum, about 2" long, and the insides of it will consist of a spring, a ball, and a ball seat. If this valve exists, remove it, knock out those inner components which will convert it to a straight through fitting, then re-install it. Hopefully that cures the problem.

The above procedure will cure a restriction problem with the anti siphon valve as stated. BUT, it may also allow fuel to drain backwards to the fuel tank when the engine is not running (siphoning backwards) due to the fact that the carburetors/fuel pump etc are higher than the fuel tank. This condition is not an absolute as the valves in the fuel primer bulb usually prevent this backwards siphoning problem. However.... if this does take place, the cure would be to install a new anti siphon valve.
 
Thanks Joe,,,,,,in looking for a fuel restriction I notised that there was NOTa anti-sipon valve at the tank ,,,but just a straight flow fitting. These are fairly cheap,so this will be my next step,,, this would make sense
 
the anti- siphon valve worked,,but what concern me is that there has not been one there for 10 years??? why a back siphon probelm to the tank now??? What has broken down,,,,fuel line leak???/cannot find it,,,,got any answers? Iam stumped
 
In all probability, the anti siphon problem for the past 10 years has been put on hold due to superior valves within the fuel primer bulb or a great air tight fuel system which now is slightly less than perfect. But if you don't see or smell any fuel leaks, don't be concerned with the question of why..... just be happy that a reasonable priced anti siphon valve cured the problem. It's usually a slightly flawed primer bulb cause.
 
Thanks for all your help Joe,,, I did find out the hard way that there are DIFFERENT spring tension on these anti siphon valves. Both were 14nip x 3/8 barb but one cause a restriction warning alarm and the other did fine (it had a slightly larger ball and throat). Maybe this info will help someone else down the road.
 
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