I have a OMC 5.8L carbureted engine. It runs fine when warm, When cold, I have to pump the throttle a few times to get it to start, and keep the throttle at fast idle to keep it running until it's warm; about 3-4 minutes. I suspect the electric choke is not functioning properly. Can anyone suggest how to troubleshoot or repair this problem?
Howdy,
Well, it might be helpful if you post your model number. There's 6 1992 models and 2 1991 models.
Yours could be any of these 8 models
Now having said that, electric chokes are pretty simple. There's a 12v heating element in a small housing on the side of the carb. The heating element of course gets hot enough to cause a bi-metallic "spring" to move the choke plate shaft to the open position once it's fully heated. (it's closed when cold)
Since it should be closed when the engine is cold that would tell you right away if it's anywhere close to being adjusted correctly.
It also should after a few minutes of being powered, begin opening the choke plate to fully open once the element is fully heated.
On the other hand, Yours could be adjusted like mine.
I disconnected it and adjusted it completely out of the picture because I only boat in warm weather so I really don't need a choke. I also have to pump the throttle and manually run the engine at a high idle when I initially start it. I don't really mind though. It doesn't take long for it to warm up and after initial start up, it starts fine for the rest of the day.
Doing that requires me to have the carb idle speed and mixture adjustment set right. I installed my Mercruiser 454 back in 2005 (or was it 2006?) and never did connect the choke at all.
I am not necessarily suggesting you do that......it just works for me......
It should be pretty easy to determine if your choke is working by first looking at your choke plate. When the engine is cold, is the plate open? (vertical) If it is, it's either adjusted like mine (out of the picture)
or it's stuck open.
Apply 12v to the heating element. (use a simple jumper wire with a 10A or so fuse...) does the element get hot after several minutes?
If it does, it might be ok and all you need to do is adjust it..... if you can move the choke plate by hand.
There should be an autochoke adjustment procedure in the following online manual if you don't have an OMC service manual
http://boatinfo.no/lib/library.html
Regards,
Rick
(I had one of those!)