update=90 150 johnson gt runs great but wont go over 2800rpm

[blue1952]

Re: update=90 150 johnson gt runs great but wont go over 2800rpm

I have a 1989 Johnson 175 GT with the same type problem. On mine when I get past 1/2 throttle or about 2800 rpm it wants to jump off the transom. It does the same thing with a hose hooked up or under a load. Both of my temp switches are open.
I have rebuilt the carbs and replaced the trigger. The power pack is an after market one that was put on before I got it. However it starts right up and runs fine until mid throttle.

Thanks in advance for any help on this..

 

[jonesg]

Re: update=90 150 johnson gt runs great but wont go over 2800rpm

I have a 1989 Johnson 175 GT with the same type problem. On mine when I get past 1/2 throttle or about 2800 rpm it wants to jump off the transom. It does the same thing with a hose hooked up or under a load. Both of my temp switches are open.
I have rebuilt the carbs and replaced the trigger. The power pack is an after market one that was put on before I got it. However it starts right up and runs fine until mid throttle.

Thanks in advance for any help on this..

Start a new thread, ya can't hijack.
Plus this is an old thread now.

 

[emdsapmgr]

Re: update=90 150 johnson gt runs great but wont go over 2800rpm

You mentioned that you cleaned the carbs on your first post. It's not unusual for dried fuel to restrict internal passages in the carb bodies. Did you disassemble them completely and remove the jets? Visually inspect each of them for debris? The passages need to be cleaned with an aerosol type carb cleaner. Spray one passage on one carb and monitor the exit flow. Then do the same passage on the next carb and check for similar exit flow, repeat on the third carb, then go to the next passage. etc. That engine shipped from the factory with plastic carb bowls. It is very common for these bowls will deform (warp) over time. When they warp, they don't seal well around the gasket surface of the upper carb body. You should replace them as they can cause fuel leaks and running issues. In some cases they can cause air leaks which will cause the engine to run lean. Reorder the same part number from the original parts list and you will receive the correct replacement aluminum bowls. You will have to replace the carb drain screws with the correct ones and mid jets from the old bowls will not fit the new bowls. Your dealer can help you get the right ones. Make sure the primer solenoid red lever is parallel to the length of that solenoid.