Problem with 1997 90HP Johnson V4 2stroke

Peahead

Well-Known Member
A mile out from the marina yesterday things were running fine then the my main motor slowed quickly losing power then died- no alarms went off, no over heat/impeller was pumping water well. It started up fine and idled ok but then upon giving the throttle it sputtered and died again. Had trouble re-starting. Kicker motor got me back to the marina and then upon starting main again it started and ran perfectly fine . Put a load on her with some fixed throttle bursts and she ran fine. Took out of marina again for test run and ran perfectly but after 10 minutes at close to full throttle the same thing happened- it lost power, sputtered and died (very similar in presentation to when the gas feed line valve has been accidently shut off) On the way in the second time on the kicker, I managed to start the main again and it ran perfectly fine again - back to the marina without issue .

It seemed like a gas blockage issue so I am thinking I should start by having the gas fiter changed. Perhaps I am just thinking positively and hoping it is the filter or a fuel block issue and not cylinder damage issue. New plugs and new battery were just installed this month as well as a new water seperator- changing plugs again made no difference. The plugs seem very soaked in gas almost as if the opposite could be true -too much gas ?? I had just topped up with a higher octane supreme gas (Chevron's non-ethanol), I doubt that could be causing this ? The motor may have had gas with ethanol run through it at some point during its life but not sure - How often would ethanol have to be run through an outboard to cause damage to fuel lines ?

Before I haul out and tow to shop ...any ideas ?

Thx
 
If you have an inboard fuel tank, check your vents for blockage. If they are salted up the engine will run until the fuel pumps can no longer suck fuel.
 
If you have an inboard fuel tank, check your vents for blockage. If they are salted up the engine will run until the fuel pumps can no longer suck fuel.
 
Trouble-shooting is always a fun game. Four basic things to look at. Spark, Gas, Air and Compression. Check for spark at the plugs when the motor is in the fault condition. If you have spark, hook a small tank to the motor and see if it will run from a known good supply of fuel. Not that I think it’s a problem but check for air by looking in the carb to make sure the butterfly is opening up to wide open with key off and control handle full forward (WOT). Compression is tested with a tester. All cylinders should be within 10 percent. In your case it does not sound like a compression problem. That covers the main systems. Once you know what system is not working you can track it down. If you are going to work on this motor yourself these links are a great resource to search for answers.

http://forums.iboats.com/forumdisplay.php?f=24
Or
http://www.marineengine.com/boat-forum/forumdisplay.php?f=26

If you think it is a fuel problem and you have an inboard tank, another common problem is the anti siphon valve. Another thing to check is the pump bulb. It should be hard when running. If it is collapsed when you are having the problem, that points to the tank and lines.

GLG
 
Trouble-shooting is always a fun game. Four basic things to look at. Spark, Gas, Air and Compression. Check for spark at the plugs when the motor is in the fault condition. If you have spark, hook a small tank to the motor and see if it will run from a known good supply of fuel. Not that I think it’s a problem but check for air by looking in the carb to make sure the butterfly is opening up to wide open with key off and control handle full forward (WOT). Compression is tested with a tester. All cylinders should be within 10 percent. In your case it does not sound like a compression problem. That covers the main systems. Once you know what system is not working you can track it down. If you are going to work on this motor yourself these links are a great resource to search for answers.

http://forums.iboats.com/forumdisplay.php?f=24
Or
http://www.marineengine.com/boat-forum/forumdisplay.php?f=26

If you think it is a fuel problem and you have an inboard tank, another common problem is the anti siphon valve. Another thing to check is the pump bulb. It should be hard when running. If it is collapsed when you are having the problem, that points to the tank and lines.

GLG
 
Thanks GLG and profisher. Thanks for the links too GLG.

I do have inboard aluminum tank and I checked the gunnel vent. Its ok with a bit of oxidation and salt but air is cruising through the screen quite freely. I got out to the boat for a very short time on Sunday ....The fuel filter was clean and the primer bulb pushes gas through the fuel filter well. It did not collapse at all when I had the problem on Sunday but it doesn't stay hard when running.I don't think it stays hard when running because once the motor is using fuel up the bulb just has gas passing through it so is not got backed up gas anymore to make it hard .
Have yet to check spark and carb. I am also thinking there might be an issue with the choke .....so maybe I can drag one of the mechanics down to the boat at my marina....only problem is they shy away from getting near an omc [}:)]

photo of fuel filter
IMG_3357gasfilter.jpg
 
quote:Originally posted by dohboy

make sure to pull plugs and see what u got, dont want ugly plugs sittin in there

Yeah, sometimes the obvious gets overlooked for more complicated but yes I did put in new plugs. After talking with Lordship just now it looks like its likely not a fuel feed issue. Priming the feul bulb while the motor stalls out doesn't seem to fix the stall issue so likely not fuel feed issue. They feel likely an electrical/ignition/stator problem but hard to solve unless the intermitten problem actually fails for them. Since they are THE omc repair place in Vancouver with tons of experience working on these motors I guess I should listen. I think I am gonna haul the old baby into Lordship even though I'd much rather not have to do that. I am good for leg oil changes and filter changes myself but beyond that I guess I will have to reach into my slim dusty wallet for this one.
 
I doubt its a spark plug issue. It sounds like a fuel issue. You should get a portable fuel tank and hose, plumb it in to your fuel inlet at your engine. Probably a good idea to mix the gas at this point as well... Take it for a run with a partner. If it runs fine, your prob's south of the fuel connection. If it starts to sputter during the sea trial, have your partner pump the bulb and see what happens. If it picks up again, then you have a fuel prob at your motor. If pumping the bulb doesnt make a difference, youll be looking for a different prob. Good luck.

untitled.jpg

Fill the dam tub!
 
quote:Originally posted by dohboy

make sure to pull plugs and see what u got, dont want ugly plugs sittin in there

That just reminded me of something that happened to me many years ago. I'd just done a tune-up on my car, and had put in brand new spark plugs. I tried a set made by Accel, the guys who made the big racing coils.

It ran great until I was on the dragstrip at Mission Raceway. As I was about to make the shift into 2nd gear and the motor was maxed out at about 5000 RPM, it just died. I backed off the throtle and it came back to life. Needless to say, I lost the race, but was able to drive the car home like nothing happened.

Turned out that it was the spark plugs had just crapped out under load. I replaced them with a set of AC's or Champions, (can't remember), and everything was fine. Just got some bad plugs.

Might be worth trying a new set of Bosch or NGK plugs.

Jim's Fishing Charters
www.JimsFishing.com
http://ca.youtube.com/user/Sushihunter250
 
Agree with IFL sounds like a fuel problem.
 
quote:Originally posted by Sushihunter

quote:Originally posted by dohboy

make sure to pull plugs and see what u got, dont want ugly plugs sittin in there

That just reminded me of something that happened to me many years ago. I'd just done a tune-up on my car, and had put in brand new spark plugs. I tried a set made by Accel, the guys who made the big racing coils.

It ran great until I was on the dragstrip at Mission Raceway. As I was about to make the shift into 2nd gear and the motor was maxed out at about 5000 RPM, it just died. I backed off the throtle and it came back to life. Needless to say, I lost the race, but was able to drive the car home like nothing happened.

Turned out that it was the spark plugs had just crapped out under load. I replaced them with a set of AC's or Champions, (can't remember), and everything was fine. Just got some bad plugs.

Might be worth trying a new set of Bosch or NGK plugs.

Jim's Fishing Charters
www.JimsFishing.com
http://ca.youtube.com/user/Sushihunter250

Thansk Jim but I already swapped out the plugs and still had the problem
 
Thanks IFL, that sounds good. I will try that before assuming an electrical/spark/stator ( or other) issue. GLG also suggested I try that but I hadn't yet explored where/how to connect the external tank hose to the main motor yet. I think I can just remove my kicker's tank gas hose connector and tie it in with a hose clamp on my main.
Good tip to mix oil to the day tank but since I have oil injection doesn't the injection system add the oil after that point anyway?
 
Its not an oil injection system, its what OMC calls a VRO pump.Yes it does mix the oil, however, if you are dealing with a VRO failure, its better to be on the safe side until you find out for sure. The VRO is your main fuel pump that also varies your oil ratio... hence VRO.

untitled.jpg

Fill the dam tub!
 
Don't use the kicker fuel line to test the main, the hose is probably to small and it will starve out at higher rpms, defeating your test. If you have an inline water separator fuel filter, disconnect the line there and connect it to the tank end fitting.
 
quote:Originally posted by profisher

Don't use the kicker fuel line to test the main, the hose is probably to small and it will starve out at higher rpms, defeating your test. If you have an inline water separator fuel filter, disconnect the line there and connect it to the tank end fitting.

Thx for the fuel line 'size' reply profisher ( and your mixed gas answer IFL )
Ok I have to admit I may sound stupid here so please be patient with me ;) ....if you look at my photo above of the fuel filter, you can see the main fuel line/hose entering the to of the fuel filter cap is quite small in diameter( where all the gas the motor needs passes through) . Why can't I just detach there and attach a portable gas supply in at that point ? If the motor's fuel line is of small diameter in the motor why would my day tank gas line have to be substantially bigger? ?? I would push mixed gas through (thanks IFL)
 
If I was doing the test, Id connect it directly to the VRO (fuel pump).Of course make sure you have a clean fuel supply as there will be no filter during the test. This will give you a clear distinction between the potential problem areas.

untitled.jpg

Fill the dam tub!
 
IFL, you are awesome man.....totally correct sir. Problem now solved. It was fuel contamination. Apparently my gas tank is being drained as we speak. There apparently was alot of water in the fuel, like alot. I have no idea how it got there but now we will try to figure out why. Last place I fueled up may have had watyer in the fuel ? or maybe it leaked through my cap ? .....or does someone hate me enough to fill my gas tank with water ? ;) Surely I don't pizz off people that much, do I ? lol

Thanks so much for everyones help on this.....it is VERY appreciated. If you are ever on the water and you see ALURE come over as I owe you beers ... I will try to keep several on board that I don't touch (just in case)!!
 
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