4.3L GMC with Cobra outdrive problems.

I am looking for some direction and am hoping that some of you can help. I bought my 1986 Crestliner Nordic from my brother-in-law last year, he bought it from my father about 8yrs ago. My dad bought it new from a dealer in Minn. So it is a family machine and I would like to bring it back. It has a 175hp GM engine with an OMC Cobra outdrive. Here is my concerns.

I was and still am somewhat having problems with hesitaion when accelerating. So I cleaned the carb, finding that it was covered in black crud, maybe the sound dampning material. After cleaning it seemed to help a lot and seemed to stop the problem, or atleast for a while.

Yesterday, I took out my boat and was having problems off and on when going from nuetral to forward. When I shifted to forward the engine began to sputter and almost hiss a little then die out while it shook. That would take a 5 seconds or so. Being a few miles from the boat ramp I decided to try it in reverse (just hoping it would run that way), and it worked perfect. Hmmmmmm. So I then tossed it into forward and it ran like a charm. Go figure. This happend off and on during the day. This is my biggest concern, but I do have a few others.

One is I am having a little trouble shifting. It does not shift hard or make any loud noises, but just a little tought to shift.

Lastly, the boat seems to pull to the left when driving.

If anyone can help I would greatly appreciate it. I am new at this and can't wait to show the Walleye's on Rainy lake what I got this summer! THX.

Re: 4.3L GMC with Cobra outdrive problems.

Welcome to iboats. I would look hard at Suzuki.

Re: 4.3L GMC with Cobra outdrive problems.

Your in the wrong forum you need to post in the I/O Mercruiser etc.section

Re: 4.3L GMC with Cobra outdrive problems.

I just gotta know, Steve.

You don't have a Suzuki. You don't have a Yamaha. You don't even have an outboard.

Why did you choose the Yamaha and Suzuki Outboard Troubles/Repair Forum?

Gone to the Mercruiser, etc. Forum.

Re: 4.3L GMC with Cobra outdrive problems.

Sound like the lower shift cable is going out. it will make the esa act funny too.

Re: 4.3L GMC with Cobra outdrive problems.

Yep, I noticed right after I posted this I was in the wrong section. Sorry.

Re: 4.3L GMC with Cobra outdrive problems.

I was and still am somewhat having problems with hesitaion when accelerating. So I cleaned the carb, finding that it was covered in black crud, maybe the sound dampning material. After cleaning it seemed to help a lot and seemed to stop the problem, or atleast for a while.

Click to expand...

The Outside of the Carb is pretty much Irrevelant,......
It needs to be torn down, Cleaned,+ Rebuilt to do Any Good........

One is I am having a little trouble shifting. It does not shift hard or make any loud noises, but just a little tought to shift.

Click to expand...

I don't do OMCs,.... But I agree that it Sounds like it Needs a Lower Shift Cable........

Lastly, the boat seems to pull to the left when driving.

Click to expand...

Adjust the Torque Tab that's mounted just above the Prop.........

Re: 4.3L GMC with Cobra outdrive problems.

Yes, I did clean the outside of the carb, but I also cleaned the inside. It was removed and cleaned.

Re: 4.3L GMC with Cobra outdrive problems.

As they said, you probably need to replace your lower shift cable, or at least adjust it and/or clean out the cavity the bellcrank is housed in...it gets full of crud. Hard shifting is a problem OMC addressed with service bulletins, and you can read about all of that here:
http://www.hastings.org/~stuart/cobra/kw-shift.html

Check out the links too.

Re: 4.3L GMC with Cobra outdrive problems.

One more thing to check: when you have the outdrive off to check/adjust/replace the shift cable, look down into the upper gearcase where the shift rod is located. You'll probably need a mirror and a flashlight. Look at the seal around the shift rod. They have a tendency to harden, or even partially dislodge, and bind the rod. There are two components; a wiper on top and a seal below. I've had the wiper pull halfway out of the housing and really jam things up. They're not too hard to replace, but you do have to split the upper and lower cases.

Re: 4.3L GMC with Cobra outdrive problems.

Once again, thank you all. I have to do some work and hope that it is only one of these things. I have found an original OMC service manual, so that should help ton.

Anyone have any good ideas on how to test any or all of these ideas on what may be wrong? I would like to be able to narrow it down. If not no big deal.