OMC cobra 5.8L dies at idle

[Dopey wan kenobi]

I have a 1990 5.8. Boat will start on choke and run in neutral but dies when returning to idle or when at idle. If it is idling have no issue shifting into fwd or reverse. Once in gear can run all day good power. This happens on the lake or trailer
I am thinking my idle is set to low. Any other ideas?

 

[Scott Danforth]

welcome aboard

your lower shift cable needs adjustment

 

[Dopey wan kenobi]

I am curious how the shift cable affects the idle in neutral, I can pull my throttle lever out engage the choke and run in neutral, it will run all rpms in neutral until I get close to idle. Also I did fail to mention as i get close to idle my rpms drop low. Not trying to dispute just want to understand the mechanisms involved and how they interact.
also any info on adjusting that word be great, am not finding any adjustment info only replacement info

 

[Dopey wan kenobi]

Lastly the boat seemed to be flooded when I attempted to restart. Could this be an issue with a sticking float or needle in the carb?

 

[kenny nunez]

Get a genuine Holley Marine carburetor repair kit for your engine. If you are unable to rebuild it try to find someone who can. Do not exchange it for a rebuilt automobile carburetor. Most likely the gasket between the metering block and throttle body have shrunk and some of the passages are blocked or there is some sediment in the float chamber.

 

[Lou C]

Your idle speed should be approx 600 rpm with the engine in fwd gear, in neutral it may be slightly higher. Try running it in neutral with a tach hooked up, note the idle speed rpms, then trigger the ESA interrupt switch. This should cause the rpms to drop to about 450 but it should not stall. If the stalls then you need to get it in a better state of tune and/or clean and rebuild the carb so it can run at least briefly at that speed. Normally when you shift on land on the water hose the ESA will not engage to lower the idle when shifting to neutral because there is no load from water against the prop. But in the water when you shift to neutral you will feel and see the idle drop to 450 very briefly as the gearcase comes out of gear back to neutral. As soon as it gets into neutral it should come back up to 600 at idle. If not the transom shift cable could be sticking. When set up properly the OMC system actually works pretty well. However if the engine is in a poor state of tune or the carb is dirty or in need of a rebuild you can have these problems.

I would not touch the cable adjustment as of yet first get the engine to idle reliably at 600 rpm and when you trigger the interrupt switch it should be able to drop to 450 rpm momentarily without stalling.

 

[Dopey wan kenobi]

Update:
I jumped the gun with having an issue. I ran most of the fuel out, cleaned the fuel filter at the carb and replaced the other. Fresh fuel no more idle or restart issue.
Thank you all for the advise, sorry to have placed the trailer before the truck!