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Jason, Marine Mechanic
Category: Boat
Satisfied Customers: 15674
Experience:  Degree in Marine Technology. Gas and diesel marine mechanic.
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I have a 2000 150 hp OB - I need to adjust the throttle

Customer Question

I have a 2000 150 hp Johnson OB - I need to adjust the throttle throw - Can youn help me?
Submitted: 1 year ago.
Category: Boat
Expert:  Jason replied 1 year ago.

Hi Raymond, my name is Jason.

There isn't really any way to change the amount of throw in the throttle, that is controlled by the linkage inside of the shifter box itself.

Do this for me, and you can do it with the engine off. Push the shifter lever all the way forward. Take off any kind of plastic cover you might have in front of the carb. Look down each each, and tell me if the throttle blade is completely open or not. It would be completely open if the throttle blade is open 180 degrees.

Customer: replied 1 year ago.
Disconneted the top two rubber holdowns - looked like the top- two are completely open - if you need info on other four, I will have to remove some housing to get at the other holdowns -
Expert:  Jason replied 1 year ago.

All the carbs should be the same. So if you can see that the top two are open then the throw is going to be correct (Again it's not something you can really change anyways)

That being said, the throw is not the problem. What is the history on this engine? Have you ever seen it make full power personally? How old is the fuel?

Customer: replied 1 year ago.
I Have never seen the engine come to full power - I have owned the boat for thrree years - same problem - I do feel a dead spot as I attempt to plane off - Very annoying - I changed the cannisted fuel filter last year - I stored it with less than a quarter tank of fuel - The engine has low hours - The previous owner stated that he did something to govern the top end to keep his kids from running at full throttle - The boat is not yet in the water - The plugs are new last year - I,m not a boat tech - but I can still swing a wrench at 84 years old - Had a Service Station when younger.
Expert:  Jason replied 1 year ago.

Have you done any spark or compression testing on the engine yet?

Customer: replied 1 year ago.
Expert:  Jason replied 1 year ago.

Fuel restriction, if the engine was starving for fuel because of a problem with the boats fuel tank, that would cause a lack of rpms. One test we always do in the shop is to run the engine off of a portable tank, and see if that helps. If it does, there is some kind of blockage or restriction in the boats fuel tank/plumbing. If that looks good, and there is no difference when running on a portable tank. Then we would remove the carbs and properly rebuild them. Does that make sense?

Expert:  Jason replied 1 year ago.

I do want to make sure you are happy with my service before you go. If you had a further question on the issue by all means feel free to ask. If not, Just in case you do not understand the way the website works (and some folks do not). You do have to put forth a positive rating in order for it to credit me for helping you. When ratings are not done, the website simply keeps your deposit and they will not credit me. The ratings box is located at the top of the screen. To rate, you must select the star you wish and also confirm it. Please let me know if you run into any problems or errors when trying to do it. If you do have a problem, or if you can not see the ratings box which is at the top of the screen. Please reply back "I rate Jason's service _______" and fill in the blank.

Questions do not close out, so if you have to come back later on with follow up questions to the issue you still can even after doing a rating.

Thank you


Expert:  Jason replied 1 year ago.

Hi Ray, just checking in. How are you making out?