OMC 2.3 rough idle, rough start, dies.

[mmmantei]

I am hoing somone can help. It seems I have multiple problems. Last fall I purchased my boat, I ran it twice with no issues. I winterized it per the service manual and tried to get it running this spring. To start it off the boat would not start. I replaced the points, condenser, cap and rotor. The engine started after that. However I have to put it in neutral and give it full throttle for it to start. And when I took it on the water as soon as I took off it spit and sputtered up to WOT. I got to my fishing spot and as soon as I turned the boat off it would not start again. It cranked and spit and sputtered I gave it full throttle and it started. As soon as I backed off and put it in gear it would die. Then I would turn th key and there was nothing, not crank, it was dead. Then I waited for my frustration to go away and it would crank, start at wide open, but not stay running.

I read through a few post's and I think I know where to start, checking the points again, check the fuel filter, check the power wire to the distributor. Where is the fuel filter located? Should I change the plugs and wires? What are the chances pulling off the carb and giving it a good cleaning would help?

Are there any cross references to plugs and wires that I can get from an auto store?

Thank you in advance for helping.

 

[danond]

Re: OMC 2.3 rough idle, rough start, dies.

Engines run badly for a few reasons but there's a couple that are pretty easy to diagnose (most of the time).

Start checking your fuel system from the pump forward. Unhook the fuel line from the carb, direct it into a container, have someone crank the engine. It should pump fuel with each revolution - quite a bit, too. Fuel pump working: Check.

Attach it to the carb again. Pump the throttle (don't start it). Watch down the carb throat while you (or someone else) does it. Fuel squirting in below each venturi? Accelerator pump working: Check.

Use a timing light. Attach it to any plug wire, connect to the battery, have someone turn the engine over. Does the timing light flash? Coil, distributor, points functioning: Check. (Doesn't mean they are adjusted properly - just that they seem to be working). Now adjust them.

Next, pour a few capfuls of fuel down the carb throat. Does the engine start, then die? Compression reasonable: Check.

Pull the plugs - are they black? Brown? White? Rusty? Corroded? Each means something different. Might not mean much in your case since it barely runs to begin with, but it's worth checking in my mind.

That's not the whole list, and I'm not a marine mechanic, but it's important to run through things like this one at a time (don't just start replacing things - that's expen$ive) so you can rule out basic issues systematically instead of jumping from one thing to the other, never really knowing what's wrong or right.

Also, if you're going to pull the carb, don't just clean it. Use a soaking solution and compressed air. Disassemble it, put a kit in there, put it back together as clean as it was when new, inside and out. Adjust it properly (meaning by the book, not by guessing), too. Saves lots of headaches.

 

[bruceb58]

Re: OMC 2.3 rough idle, rough start, dies.

When you changed the points did you use a dwell meter? Did you check your timing after you did that?

 

[mmmantei]

Re: OMC 2.3 rough idle, rough start, dies.

When you changed the points did you use a dwell meter? Did you check your timing after you did that?

I did not use a dwell meter. I guess I am not familiar with that process. I do have a service manual. I will check that out for adjusting dwell.

 

[becon776]

Re: OMC 2.3 rough idle, rough start, dies.

bump this situation!! haha.
Yeah had a 21 ft bayliner capri for five years. OMC 2.3 liter.the thing has NEVER idled right. I am about to sell it soon and the buyer is a coworker so I would love very much to get things as right as possible.

cold start - no pump = no start----- 3 pumps last one while turning key = start when I drop to neutral idle position it stalls. leave it running for a while and i can drop it there somewhat. as soon as i put it in reverse it stalls. i have to give it quite a bit of reverse throttle and then quickly shift it into forward gear with liberal throttle to go.

drive for 5 min it comes up to temp and it idles beautifully. forward and reverse. coming back into dock everything is perfect or when rafting up. Once it's hot it's good. Turn it off on the water and it's a similiar situation only easier because I can just quickly put it into gear and give a little throttle.

Launch ramp NIGHTMARE!!!!!! I am going insane chasing this issue down.

history: plugs replaced every year.... 2010 plugs, condensor, distributor cap, points all replaced by old school boat mechanic. 2010 carb rebuilt. I thought the carb rebuild would have been my answer but nope.