Bogging & backfires... Help! 2.3 Ford OMC Cobra

[Baylinercapri1987]

I have a issue with my boat engine right now, Bogging down off idle, and backfires when I try to give it gas. I have replaced the spark plugs, fuel filters (carb & separator), Checked the timing belt/distributor placement & everything is aligned, Timing is right at 10 as it should when its idling. Checked the compression, its all good and even.... I took apart the carb and cleaned it with carb cleaner.... Idle got better & not as much backfires but still does it. I am thinking fuel pump or something is going on with the carburetor.... Any ideas?

 

[Bondo]

Re: Bogging & backfires... Help! 2.3 Ford OMC Cobra

I am thinking fuel pump or something is going on with the carburetor....

Ayuh,... I completely Agree...

 

[Baylinercapri1987]

Re: Bogging & backfires... Help! 2.3 Ford OMC Cobra

Thanks.... Nice to know I'm thinking in the right direction here... Its a pretty simple engine in my mind. One question.... Would you rebuild the carb or buy a fuel pump first?

 

[turbinedoctor]

Re: Bogging & backfires... Help! 2.3 Ford OMC Cobra

I would think rebuilding the carbs would be first if it runs. Try pulling the top off the carb after you shut it down and see if the fuel bowl is full. If it is, your fuel pump may not be the problem. If its not full check to make sure the float is adjusted correctly. If float is adjusted right and bowl still is not full after running then I would say the fuel pump may be bad.

 

[fossill]

Re: Bogging & backfires... Help! 2.3 Ford OMC Cobra

Fuel pump is easy to check. Check the suction and output using a gage before you condem it. Why throw parts at it when some simply diagnosing and troubleshooting in an orderly fashion will lead you to the problem. Also check for vacuum leaks. They are the cause of a lot of" idle" problems.

 

[Baylinercapri1987]

Re: Bogging & backfires... Help! 2.3 Ford OMC Cobra

Fuel pump is easy to check. Check the suction and output using a gage before you condem it. Why throw parts at it when some simply diagnosing and troubleshooting in an orderly fashion will lead you to the problem. Also check for vacuum leaks. They are the cause of a lot of" idle" problems.

No gauge for fuel pressure right now.... I guess I need that in my tools? Um yea. I would really like to test the FP at this point... any rec's on a gauge? No leaks, its idling just fine right now.... Maybe I will throw up a video, more opinions so I don't waste a bunch of money!

 

[fossill]

Re: Bogging & backfires... Help! 2.3 Ford OMC Cobra

No need to spend a lot on gages. I get mine from local auto parts stores. I forgot to mention to check the flow also on the pump.
Also, make sure the accellerator pump circuit of the carb is working. To check disconnect the throttle linkage and look down the bore of the carb while rapidly opening the throttle on the carb to full. You should see a good stream of fuel being injected into the bore of the carb. If its not working you will get a hesitation/bog on throttle advancement. I assume all the work done so far has been done in accordance with the instructions in the service manual?

 

[Baylinercapri1987]

Re: Bogging & backfires... Help! 2.3 Ford OMC Cobra

Will check for a gauge at the auto parts store tomorrow, will also check the flow & the accelerator pump circuit.... I was getting a slight hesitation/bog before the issue... I think its connected to my larger issue now. Got no help from the service manuals, I'm a pretty good back-yard mechanic... although I do own 2 books for this engine.

 

[dirtdiver]

Re: Bogging & backfires... Help! 2.3 Ford OMC Cobra

I have the same problem on a merc 3.7. Its getting fuel. My next step is a carb rebuild. then check for sticking valves and the cam for bad lobes. I replaced my points and coil too.... so if something works Ill let you know.

 

[Baylinercapri1987]

Re: Bogging & backfires... Help! 2.3 Ford OMC Cobra

Replaced the carb with another good used one, same thing.... hard to start, and when it finally does fire it will not get past idle, just bogs out and sorta backfires. The fuel pump is pumping strong & healthy.... tested into a catch can. Any help?

 

[dirtdiver]

Re: Bogging & backfires... Help! 2.3 Ford OMC Cobra

what kind of distributor do you have? If you have points, check the points and then uder the plate check the advance.

 

[Baylinercapri1987]

Re: Bogging & backfires... Help! 2.3 Ford OMC Cobra

I got the Mallory points and condenser style... I think the points/condenser were changed out last season... I am starting to think valve problems now, but ???

 

[JustJason]

Re: Bogging & backfires... Help! 2.3 Ford OMC Cobra

What are your actual compression numbers? What is the base timing and dwell set at?

 

[Baylinercapri1987]

Re: Bogging & backfires... Help! 2.3 Ford OMC Cobra

Did not write the #'s down, but in range from each other & in the mid 100's.... will get them tomorrow.... Timing was at 10 running, and everything lined up on tdc #1. Just got a dwell meter the other day, so will try that out tomorrow as well.

 

[cr2k]

Re: Bogging & backfires... Help! 2.3 Ford OMC Cobra

A real cheap way to eliminate is to change to points AND condenser. I bet it will go a long way. A bad condenser will act as you explain. I just had that problem last week.

 

[dirtdiver]

Re: Bogging & backfires... Help! 2.3 Ford OMC Cobra

check the advace. take the plate off under the points. I had that problem

 

[Baylinercapri1987]

Re: Bogging & backfires... Help! 2.3 Ford OMC Cobra

Replaced the points & condenser and I get the same thing.....

 

[jaysnewboat]

Re: Bogging & backfires... Help! 2.3 Ford OMC Cobra

I am having the same type of problem with my mercruiser inboard 4 cylinder when I throttle up with no load(neutral) the engine revs fine. As soon as I put a load on it I throttle up and it revs up for like 45 seconds and then the engine bogs right down?? I can run at low throttle engine runs fine but as soon as I WOT the engine bogs right down. I have changed all the regular items points, condenser, coil, plugs, wires fuel filters etc. Even replaced the Carb with a factory rebuilt. Still having this problem. I noticed in this thread I believe Jason said remove the base plate on the distributer and there was timing adjustments there?? Can someone please give me some information on how to do a complete timing alignment. I have a feeling that the all the components are not set to top dead center because when I was adjusting the timing way out of scope seemed to make it run better.

Thank you in advance.

No pun intended.

 

[dgopetactical]

Re: Bogging & backfires... Help! 2.3 Ford OMC Cobra

What pressure is your fuel pump pumping? I had a simular problem before and i installed a inline pressure gauge between the carb and pump i come to find i was only getting 2psi when i should of had 5-6psi. I installled a new fuel pump and got the 6psi and the problem went away.
Just because your getting fuel out of the pump does not proove your getting the correct pressure. Test the fuel pump pressure and make sure its in the proper range for your engine. No matter what i would stay focused on the fuel delivery. Jumping around will only get you confused, trust me ive been there.
Denny

 

[rosgood14]

Re: Bogging & backfires... Help! 2.3 Ford OMC Cobra

I am having a problem with my motor backfiring as well except i have yet to get mine started. the motor is getting fuel and it is getting spark to the plugs. it is not a blue spark but there is plenty of orange spark. it has a points system and they are clean and it has a new distributor cap. The timing is not perfect but we have got it close enough to where it should start. The motor tries every so often to fire but just not getting enough to crank. It is also backfiring to through the carb while trying to start it. We have played with the timing and it still backfires. Also the motor is turning over and every rotation or every other rotation it sounds like the motor boggs down for just a sec. i took fuel pump and the alternator and disconnected the belts to see if it was one of them crapping out but that was not the case it is something with the motor itself. I know the motor is a 1971 ford industrial motor and from what i have been able to gather it is a windor and i was told by the previous owner that it is a 351. how would i be able to determine for sure if it is a 351 windsor or not. thanks

1972 20' Penn Yan
1971 Ford inboard