omc 4.3 liter cobra v6 wont stay running

jcksn11102 · Mar 26, 2013

i have a 1990 196 fun runner and cant get it to start after sitting 1 year. i have replace all plugs,wires,rotor,distributor cap,
ign. coil, and check all fuses, etc. i did replace fuel filter water sep. but did not prime the new filter and did drain all old gas and put new gas. all i come up with that the fuel pump is bad because i took hose off and tested with turning the over and nothing came out of line. i did discover as well that my transparent line(orange) to carb. has a oily feeling on it. please help
me guys

RogersJetboat454 · Mar 26, 2013

Re: omc 4.3L cobra wont start

Re: omc 4.3L cobra wont start

Welcome to Iboats.

The line from the fuel pump to the carb has an oily feeling, but is there any fuel in it? If there is, thats a sign that the fuel pump diaphragm has ruptured.

Theoretically, the fuel pump should have enough pull to prime the system within a minute or two of attempting to start it.
Two things you can do to try to see if it's a supply or fuel pump issue;

First thing is get your self an outboard fuel line with the squeeze bulb, the universal type with no connectors on either end. Connect it between your fuel pumps inlet, and the supply line (make sure the flow arrow is pointing to the pump). Start squeezing to see if you can prime the pump. If you are able to get fuel to the pump, remove the line, reconnect the pump to the fuel system, and try starting it with your now primed system. If it won't pull fuel either, than you may have an air leak in the line, the anti-siphon valve may be jammed up, or the pickup tube in the tank may be restricted.

Another thing you can do to check the pump is run a fuel hose directly from the inlet of the pump to a small container of fresh fuel. DO THIS IN A WELL VENTILATED BILGE! If the pump is able to pull fuel out of the small tank, you know it at least partially works (ability to draw fuel from long distance may still be an issue). If it won't than I would say the pump is an issue.

jcksn11102 · Mar 26, 2013

Re: omc 4.3L cobra wont start

Re: omc 4.3L cobra wont start

thanks for the info!! i will try this this evening when i get home from work and let you know ASAP.

bruceb58 · Mar 26, 2013

Re: omc 4.3L cobra wont start

Re: omc 4.3L cobra wont start

You need to determine if you have an ignition or fuel problem first. Just as a quicky test, pour a couple ounces of fuel down the carb throat and see if it will start. If it does, you need to look at your fuel delivery. If it doesn't, it is probably lack of spark.

wrench 3 · Mar 26, 2013

Re: omc 4.3L cobra wont start

Re: omc 4.3L cobra wont start

It can take a while to draw up fuel with both the carb and the fuel water separator dry. If it starts when you prime the carb throat, do it a couple more times to see if it will keep running.

jcksn11102 · Mar 28, 2013

Re: omc 4.3L cobra wont start

Re: omc 4.3L cobra wont start

I went on and install new fuel pump and did the gas pouring down carb and it did turn on until it was dry.so what now? And where is the anti siphon vavle located at and pick up tube? Thanks for all your time and patience

bruceb58 · Mar 29, 2013

Re: omc 4.3L cobra wont start

Re: omc 4.3L cobra wont start

Do what wrench said and repeat a few more times. The problem is that you didn't fill the new filter with gas first. It always takes a long time to refill those and which is why I always pre-fill them.

jcksn11102 · Apr 1, 2013

Re: omc 4.3L cobra wont start

Re: omc 4.3L cobra wont start

i did prime the new filter as well, but it still wont stay stay running after pouring gas down the carb. a couple of times so where is the anti siphon vavle located at and pick up tube?

Don S · Apr 1, 2013

Re: omc 4.3L cobra wont start

Re: omc 4.3L cobra wont start

Either there is an air leak in the fuel system leading up to the pump, or possibly the pickup tube, or anti-siphon valve are plugged up.

Something is preventing fuel from getting to the fuel pump.

Hook up a remote fuel tank (outboard tank) directly to the fuel pump and see if it will keep running.

jcksn11102 · Apr 1, 2013

omc 4.3 liter cobra v6 wont stay running

i have a 1990 196 fun runner and after sitting 1 year. i have replace all plugs,wires,rotor,distributor cap,
ign. coil, and check all fuses, etc. i did replace fuel filter water sep. but did prime the new filter and did drain all old gas and put new gas. Replaced the fuel pump with new one. i poured gas in carb a couple of times and it ran for a second or two but wont stay running. can some tell me could it be the anti-siphon valve may be jammed up, or the pickup tube in the tank may be restricted and what they look like plus locations? please help

Silvertip · Apr 1, 2013

Re: omc 4.3 liter cobra v6 wont stay running

If you poured fuel into the carb and it briefly ran you obviously have a fuel delivery issue.
1) Make sure the vent is open on the fuel tank
2) The anti-siphon valve is the fitting on the fuel tank that the fuel line connects to.
3) The needle and seat inside the carb may be stuck shut preventing fuel from entering the carb. It would be a good idea to rebuild the carb anyway due to the long period of non-use.
4) Disconnect the outlet line on the fuel pump or at the carb. Using a container, crank the engine to see fi the fuel pump is actually pumping fuel. If so, you have a carb issue. If not, its a fuel supply issue or an incorrectly installed fuel pump.
5) The pickup tube is the vertical tube inside the tank that runs from the fuel line/anti-siphon valve down into the tank.

Lastly -- Stay in one thread so we don't have to jump around.

jcksn11102 · Apr 1, 2013

Re: omc 4.3 liter cobra v6 wont stay running

oh! by the way how do you un jam the anti-siphon valve if it is?okay i will do this and get back with you. and i will stay in same thread from now on. sorry and thanks for the help

wrench 3 · Apr 1, 2013

Re: omc 4.3 liter cobra v6 wont stay running

Put a vacuum gauge on the inlet of the fuel pump and see if you have vacuum when cranking. If you have vacuum, tee the gauge into the inlet line and check again. If the vacuum is high, something is plugged up. If it's low, splice in a piece of clear line and see if any air is being sucked in.

jcksn11102 · Apr 1, 2013

Re: omc 4.3 liter cobra v6 wont stay running

okay i will try this today. i think when i siphon the old gas out, i may picked up trash from bottom of tank too to cause a blockage on pick up tube or the anti siphon valve like Don S. mention ealier in post.

jcksn11102 · Apr 2, 2013

Re: omc 4.3 liter cobra v6 wont stay running

i went yesterday and did the testing you all asked for and found out the anti-siphon valve was jammed so i cleaned it up real good and now getting gas to carb. i did try to start it but it woudnt turn on and i did pour gas in the carb to prime it, so i dont know maybe i put too much and flooded it. I also notice the spark plug wiring and added some pics to see if they are hooked up right as to my manual pic.so what do i need to do now?

jcksn11102 · Apr 2, 2013

Re: omc 4.3 liter cobra v6 wont stay running

RogersJetboat454 · Apr 2, 2013

Re: omc 4.3 liter cobra v6 wont stay running

All the manual can tell you is the firing order. Any one of the connectors on top of the cap can be designated as cylinder #1 depending on how the distributor was installed. If you haven't touched the wires since you got it to fire by pouring fuel into the carb, I would leave them alone, and focus on the possibility that the engine is flooded.

Try opening the throttle up all the way while cranking the engine to see if it will clear the flood.

jcksn11102 · Apr 2, 2013

Re: omc 4.3 liter cobra v6 wont stay running

okay i will try that then because i notice it had gas sitting inside carb flap until i open it up. will let you know. thanks,

Silvertip · Apr 2, 2013

Re: omc 4.3 liter cobra v6 wont stay running

Cylinders are numbered 1,3,5 on the left (pport) side of the engine and 2,4,6 on the right (starboard) counting from front to back. ensure you have them on the correct cylinders. But if you hadn't messed with them since the last time the engine ran they should be correct now. But since you replaced the distributor cap, you had to pull them from the old cap and install them on the new one. So if you didn 't do that right that will need to be corrected. Put the timing mark at TDC on the compression stroke. See where the distributor is pointing. If it is not a #1 cylinder you have the firing order hosed up.

jcksn11102 · Apr 2, 2013

Re: omc 4.3 liter cobra v6 wont stay running

i did replace distributor cap too but i took off one wire at a time. if you look at my thread#17 at the pics please. It seems to me the distributor is pointing between 2 and 1. what do you think? is that right?

omc 4.3 liter cobra v6 wont stay running

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