Stuck Throttle Solid.

[sogood]

Going through my new to me boat, I got my shift cables adjusted and all seems well in that respect. However, I find that the throttle control on the actual carburettor is stuck, pretty solid. I've sprayed it liberally with WD40 and shall wait until tomorrow to see if there's any change. I've disconnected the cable, which moves freely, so the issue is with the control itself. The linkage between the throttle and the second pair of (rear) flaps moves freely, but everything else stays stuck. Forgive my lack of correct terminology!

​Wondering if this is a common issue and just down to lack of use or am I missing something? The carb is a Rochester Quadrajet and is a professionally rebuilt unit, done by the PO. Any thoughts welcome.

 

[Bt Doctur]

guessing the throttle plates are in backwards remove the carb and post some pics on the underside

 

[tlewis1]

I would also suggest pulling the carb off and having a look from the underside.

 

[sogood]

Thanks for that. I have the original carb that came with the boat, so I have a reference point. Will look see in the morning, though I can't see how it might have been rebuilt wrong and fitted without any testing. Thanks again.

 

[Bt Doctur]

You would be surprised what mechanics can do when there disturbed for any reason during a rebuild

 

[sogood]

So, I pulled the carb off for a closer look and can't see anything obviously wrong. As mentioned, the larger/secondary flaps open effortlessly. I continued to soak the relevant parts all day after removing a lot of the fiddly bits, including disassembling the throttle control mechanism itself. I took the top off the carb for a better look from the opposite side and again, can't see any obvious obstructions or issues.

​When I try to open the flaps by rotating the shaft that they sit on, there's just the absolute tiniest bit of movement at the control end of the shaft. You can see the flap barely moving, just a tiny fraction, but the next flap doesn't appear to move at all. It's as though the shaft is seized in the middle. The fixing screws for the flaps are "inside " the carb on the top side of the shaft, so I can't remove them. While I'm at it, I'm cleaning and tidying as I go, as the carb has sat for quite a while after being rebuilt and there is a lot of white powdery build up inside.

​Still spraying WD40 on the offending parts and I'll be away working for the next 5 or 6 days, so maybe when I get back it will have magically freed itself up! We shall see. In the interim, any suggestions welcome.

 

[wahlejim]

Complete carb re-build and cleaning. If it has been sitting for that long, it needs to be cleaned up.

Does your shift cable move when disengaged from the throttle on the carb?

 

[sogood]

Complete carb re-build and cleaning. If it has been sitting for that long, it needs to be cleaned up.

Does your shift cable move when disengaged from the throttle on the carb?

That's What I'm trying to do. And yes, the cable moves freely. I have much of the carb broken down and I'm cleaning as I go. But if the flaps stay stuck it doesn't help a lot. I'll continue to soak and see how it goes. Thanks for the response.

 

[wahlejim]

WD-40 may not be the best solution on this one. If it is stuck, there may be some gunk that has to get dissolved to free it up, then lubricate. Try a carb cleaner bath. Fill up a tub with a lid just slightly larger than the carb with carb cleaner or sea foam, drop the carb in and soak overnight.

 

[Bt Doctur]

If it is the throttle plats in the primary take the carb apart . 3 or 4 screws and the throttle plate comes off.
http://www.bdub.net/manuals/Quadrajet_Service_Manual_1981.pdf

 

[harleyman1975]

I suggest acetone and transmission fluid to soak it in.75% 25% mixture.

 

[sogood]

Free again! I separated the relevant section from the rest of the rest of the carb and removed the flaps, giving better access for the penetrating oil, and left it soak some more..........but still no movement. Then today I took a different approach and managed to drive the shaft/spindle out of the carb body. I placed a wooden block in my bench vice, with a deep hole drilled down into it. Then I sat the carb section onto the block, with the part of the shaft that was protruding ( the control assembly end) down into the hole. This helped keep the carb secure and gave somewhere for the spindle to go. Then, with the opposite end of the shaft protected with a piece of hardwood, I began tapping, steadily, solidly, with a small hammer. And it moved!! It still wouldn't rotate, but it was moving. I continued and then used a drift to drive the shaft all the way through.

​I thought maybe the shaft was slightly bent, causing it to jam up when passing through the separate sections of the carb housing, but a steel rule said otherwise. Straight as a die. So, using cotton buds, I cleaned out the bores that the spindle passes through and cleaned up the spindle itself, though it wasn't showing any crud or deposits. Maybe it was knocked free during the "tapping".

​End result is, it's back in place and turning freely with no hesitation, flat spots or wobbles. happy days. Now I can rebuild the carb when my kit arrives next week. Work takes me away until then, but happy to have it sorted. Thanks for the suggestions and input.

 

[sogood]

So I got back home yesterday after being away working and my latest box of parts arrived the same day. So today, armed with my rebuild kit, I put my carb back together, having thoroughly cleaned everywhere. I took my time, double checking everything and now it's back on the boat. I want to re-route the throttle cable, just to take a sharp bend out of it, but everything is working freely.
I hope to fire her up in the next few days, so fingers crossed all I'll need is little fine tuning. Thanks for all the suggestions.

 

[harleyman1975]

Excellent!