Shift Cable Replacement

[jrsick]

My throttle will not advance past 45 degrees or so of travel. It used to go 90 degrees plus before my overheat.
I've also noticed that the shift pin on the lower unit does not move when I move the throttle lever from reverse, to neutral, then forward.
Are this symptoms of a failed shift cable?
Any suggestions you have would be most appreciated.

[mmwjr]

Originally Posted by jrsick

My throttle will not advance past 45 degrees or so of travel. It used to go 90 degrees plus before my overheat.
I've also noticed that the shift pin on the lower unit does not move when I move the throttle lever from reverse, to neutral, then forward.
Are this symptoms of a failed shift cable?
Any suggestions you have would be most appreciated.

Try disconnecting the helm shift cable at the shift bracket to see if the throttle moves full range. Try shifting the lower cable at the shift bracket with it disconnected to see if you can get it into and out of both forward and reverse.

[jrsick]

Thanks Mike.
I disconnected the throttle cable from the carburetor, and now the throttle lever moves normally. No binding in the cable or throttle handle.
The problem is at the carburetor, I can't manually open the throttle. It's frozen.
Do you think some Seafoam down the carb would loosen it up?
Mercruiser manual doesn't address this condition, so starting my online research.

[Gugi47]

Originally Posted by jrsick

Thanks Mike.
I disconnected the throttle cable from the carburetor, and now the throttle lever moves normally. No binding in the cable or throttle handle.
The problem is at the carburetor, I can't manually open the throttle. It's frozen.
Do you think some Seafoam down the carb would loosen it up?
Mercruiser manual doesn't address this condition, so starting my online research.

Kano-Kroil is the best.

https://www.ebay.com/itm/Kano-Labs-A...MAAOSwnN5bgaDt

You can try in some industrial places in your area. Like Bearing sale, auto-moto, etc.

[jrsick]

Thanks Gugi. I've been using some carburetor cleaner with no luck. I removed the carb and have it soaking in carb dip now. This is what it looks like. After the carb dip does its thing I'll be able to tell how much of this is varnish and how much is rust. Any rust and I'll probably go with a new carb.

[mmwjr]

That’s a lot of tarnish. Aluminum and brass should not have rust, get some carb spray cleaner as well to blast the throttle plates. May be time to just rebuild it.

[jrsick]

Two hours in the carburetor dip and the throttle lever still won't budge. I'll soak it again today then start looking for a new carb if its still frozen.
I've never seen this situation before and am stumped. Can a varnish build up in the barrels be enough to cause this? It's a fairly simple design.

[jparsons121]

Varnish would make it sticky, but my best is on corrosion in the journals the shaft runs thru. Two different metals and the natural spot for moisture to collect.
Hit it with the Kroil or PB Blaster after the soak.

[mmwjr]

Originally Posted by jparsons121

Varnish would make it sticky, but my best is on corrosion in the journals the shaft runs thru. Two different metals and the natural spot for moisture to collect.
Hit it with the Kroil or PB Blaster after the soak.

Agree. The shaft bushing may be bad and will cause a vacuum leak.

[Gugi47]

Originally Posted by jparsons121

Varnish would make it sticky, but my best is on corrosion in the journals the shaft runs thru. Two different metals and the natural spot for moisture to collect.
Hit it with the Kroil or PB Blaster after the soak.

Kroil? That's for rust only....Hmmmm or I'm wrong again.....

[jrsick]

I went with jparsons advice and gave the carb several shots of PB Blaster and a few hours to penetrate. I sat the carb on its side and gave the blaster some time to penetrate the shaft. I soaked the carb in Evaporust for 3 hours. Still frozen so I'm going with a new carb. Even if the throttle started moving I wouldn't trust it.
I think I'm going with a Sierra carb (18-79994N). It will get here on Tuesday so Labor Day weekend is still on! Let me know if you have any tips for installing a new carb.
Thank you for the excellent suggestions.
Don't go away, I've got a question about exhaust bellows coming this week.

[mmwjr]

For clarity rust is iron corrosion, for all other metals the proper description is just corrosion.

Seems odd that all this soaking and cleaning did not free it up somewhat. When was the last time it had movement?

[jrsick]

It was used last in June, that's when I had my overheat.
This boat has not had much use. It doesn't have an hour meter. The guy I bought it from estimated it to have less than 75 hours on it, which is not much for a 2006. The first thing I did after buying the boat was look at the manifolds, risers, and ignition system. All were pristine and I tend to believe the low hour claim.
I'm finding that an extremely low hour boat can be a bad thing sometimes.

[mmwjr]

Yep, I bought my 1997 in 2008 with 163 hours and by 450 hours the main bearing were shot.