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Yachtwork, Marine Engineer
Category: Boat
Satisfied Customers: 3416
Experience:  MEC3 and RYA Yachtmaster Ocean
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Mercruiser 3.0 engine starts but throttle seems to be

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Mercruiser 3.0 engine starts but throttle seems to be disconnected. I can see the rods on the side of the engine moving when I shift the throttle lever but nothing happens with the carb or engine revs
JA: Sometimes things that you think will be really complicated end up being easy to fix. The Marine Mechanic I'm going to connect you with knows all the tricks and shortcuts. Tell me a bit more about what's going on so the Marine Mechanic can help you best.
Customer: Can’t tell you any more.
JA: Is there anything else the Boat Mechanic should know before I connect you? Rest assured that they'll be able to help you.
Customer: The boat is new to me, I saw it running stationary and the previous owner was reputable.

I've been working hard to find a Professional to assist you with your question, but sometimes finding the right Professional can take a little longer than expected.

I wonder whether you're ok with continuing to wait for an answer. If you are, please let me know and I will continue my search. If not, feel free to let me know and I will cancel this question for you.

Thank you!

Hello, welcome. Who do I have the pleasure of speaking to? My name is***** am here to help. I have been in the marine industry for 25+ years and have been a licensed Marine Engineer since 2009. I like to think outside the box and was part of the team that set the UIM Round The World Speedboat Record. I would like to be your requested tech when you have boat issues. I will be happy to help you.

I know that can be frustrating. Hopefully, we can get you back on the water quickly.

Are you at the boat now?

This is strange. What we need to do is remove the air cleaner so we can look straight down the carb throught. The opening should be mostly closed due to the butterfly valve being closed. We want to see if that butterfly is opening when we throttle up.

The first photo is the carb in idle position. That is the closed butterfly valve we see. Then the third photo is the butterfly valve open just a bit. About 25% or so. We want to check if your butterfly valve is doing this movement.

Customer: replied 2 months ago.
Since posting my question and waiting for a reply I have found that it was the throttle linkage that was seized and I have freed that up now. Next problem was the throttle return spring being stretched and I am just now making a new spring to enable the carburettor/engine to return to tickover. Whilst messing about with this I also find there is a lot of slack in the throttle cables so my next job will be to try and find some adjustment - any ideas?

Hello again- I am just now reading your text. So far so good. Nice work finding the jam up.

On the slack in the throttle cable what you can do is have a helper slowly wiggle the throttle lever and everywhere there is slack we have to fix it. That can be by replacing parts, adding washers, and sometimes guys will use a spring to keep the throttle loaded to one side of the play so that kind of gets rid of the play.

How does that sound?

Customer: replied 2 months ago.
Like the idea of the spring.

So to use a spring to take up the slack we use a larger return spring on the throttle and then tighten the tension adjustment on the throttle handle. This then wants to walk easily to idle but we push a bit harder to get throttle.

I did my best to answer with the information I had. I hope it helped with the project.

You might want to mark me as a favorite Expert and then on your next question you can request me and we can pick up where we left off.

I hope I was able to answer your question. If you would like to ask me another question in the future, you can add me as a favorite Expert. You'll have the option to do that on your "My Questions" page if you choose to rate our interaction or you can request me by name if you wish. My name is ***** ***** I go by Yachtwork on the site.


Yachtwork, Marine Engineer
Category: Boat
Satisfied Customers: 3416
Experience: MEC3 and RYA Yachtmaster Ocean
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