2.3L OMC cobra stalling and no start issues after 15-20 mins of run time

[durs22]

First time asking a question on here so hope im doing this right. This is my first time owning a boat and i need help. This boat is driving me crazy. I have a 89 omc cobra with a 2.3L ford inboard. i completely tuned it up, rebuilt the carb the whole nine yards by the book. It starts right up and runs great! first time out it runs perfect all day. second time out after boating for 15 20 minutes it will stall and not start back up. Engine temp is perfect and im getting fuel. if i sit for 5 10 mins n let the engine cool. it will start but be hard to start. If i keep pumping the gas it will start n then idol fine. Then Its back to running perfect and i can fly around for another 15 20 mins. Then back to stalling out and waiting five mins until something cools down n back to running great. ( thinking i got a bad coil and it is over heating with no spark) so i install second new coil. The first time out on the water with new coil everything goes great! Runs perfect for hours! Next time i take it out i am have the stalling problems again after running for 20 mins. so i thought it was the resistor wire off the alternator over heating the coil. so i installed a regular auto resistor. Ran it in between the ignition and the coil n disconnected the resistor wire off the alternator. Only difference instead of getting the 9 volts it needs to the coil Im down to six volts. i also replaced the coil again. Thought that would solve the problem. Same thing happens. First day out on the water with a third new coil i have no problems. thought it was fixed. nope! Take it out week later n it runs great for 15 20 mins n then stalls.... wait five mins and runs great again. Am i over looking something? maybe rpm gauge is screwing up the coil? Should i get a coil with a built in resistor n just take out the external resistor all together? Im pulling my hair out of my head trying to figure this out. i been working on cars and bikes for decades. Just never owned or worked on a boat. I thought i can fix anything until i got this boat :-(

 

[HT32BSX115]

First time asking a question on here so hope im doing this right. This is my first time owning a boat and i need help. This boat is driving me crazy. I have a 89 omc cobra with a 2.3L ford inboard. i completely tuned it up, rebuilt the carb the whole nine yards by the book. It starts right up and runs great! first time out it runs perfect all day. second time out after boating for 15 20 minutes it will stall and not start back up. Engine temp is perfect and im getting fuel. if i sit for 5 10 mins n let the engine cool. it will start but be hard to start. If i keep pumping the gas it will start n then idol fine. Then Its back to running perfect and i can fly around for another 15 20 mins. Then back to stalling out and waiting five mins until something cools down n back to running great.

Howdy,

Welcome aboard!

You say that you have enough fuel but if it stalls after 15 or so minutes it "sounds" like fuel. It's very possible that you have a blocked fuel tank vent. If the vent is clogged (or partially clogged), this *could* happen.

Take it out and run it until it quits. right after it quits, go back to the fuel cap and remove it...Is there a "sucking" sound? If there is, you have a clogged vent on the tank. Running the engine produces a vacuum in the tank. when it becomes so great that the fuel pump cannot over come it, the engine quits. Once the engine is off, with the suction gone, the air slowly leaks back in.

You might try getting a small fuel tank and feeding the engine from that. If you have the same problem, put a gage on the fuel pump (you want around 3-6 PSI or so)

It's possible that you have an ignition problem but I would start with fuel. It really sounds like fuel starvation.

First time asking a question on here so hope im doing this right.

Have a look at https://forums.iboats.com/forum/eng...69-must-have-technical-information-for-diyers

There's a lot of info in there on what you should post to help us help you!

Regards,

Rick

 

[durs22]

Thank you for your reply. I was checking over everything today. I did find the dwell was off. Was reading 31 degrees and should be 34-38. I adjusted my points and timed it again. I also found cylinder 4 spark plug was loose. After it stalled out on me in the yard and wouldn't fire back up. I shook the spark plug and wire it started right back up. Don't know if that was my problem the whole time lol
You say fuel starvation. I thought the same thing but when i pump the throttle fuel squirts inside the carb. It doesn't even attempt to start when theres fuel being shot into the carb. Thats why i was always leaning towards spark. I did check the vent hose and it wasn't clogged. Im taking the boat out tomorrow. my luck the simple loose plug is not going to be the answer. So i am taking all my tools with me and a extra fuel tank. so when it does stall out i will know if its spark or fuel. i also disconnected my tach gauge just in case. Because its stuck on 1100 rpm and doesn't move much when the boat is running. might as well get rid of the gauge to play it safe. I have a multi volt meter that gives me rpm.

 

[KG ON]

If it happens again, with the key in the on position use a jumper wire from the negative side of the coil and scratch a ground, if it sparks then the coil is fine. You could potentially have a bad condenser. Also if my memory serves me correctly the 2.3 fords have an issue with the distributor wearing out, check under the plate for metal shavings, it causes ignition problems on these. Your right about the tach disconnecting to be safe, grey wire on the coil. If the coil test passes, take the distributor cap off and crank the engine and visually check if the points are sparking. Not a perfect test but you can put an ohmmeter on the condenser positive on the wire side, ground on the metal body, ohm meter resistance should continually go up until it becomes open/OL if the condenser is good. Also make sure the black piece on the wire going into the distributor is not hitting ground.

if its fuel related check the antisiphon valve or pickup. Best way to troubleshoot fuel to start with that I've found, is hook a small portable marine tank and primer bulb to the fuel pump.

goodluck.

 

[Efini Motorsport]

It may not be the same issue or even helpful but I had a 3.0 Merc engine with a bad thermostat that would die out if I ran anything over 1/3 throttle for any length of time. When it died it didn't want to restart without sitting a little while. Changed the thermostat and it ran great at any speed.