Johnson 97 150 HP Ocean Runner starts idling fast when engine is hot

[ecelani]

Engine is a Johnson 1997 150 hp outboard with six carbs, when I run the engine for an hour or so it is OK. Then it starts to idle up to 3000 rpm and it will slow, then rev up and down. When this happens the engine will also rev up and down under load. After it sits an hour or more then it runs OK. Then when I take the boat out again the engine will do the same thing. This only happens when the engine is hot.

 

[Dhadley]

Re: Johnson 97 150 HP Ocean Runner starts idling fast when engine is hot

Welcome!<br /><br />It would really help to know which model 97 Johnson you have. Its one thing if its a 2 hp but an entirely different deal if its a Ficht.<br /><br />Good luck!

 

[ecelani]

Re: Johnson 97 150 HP Ocean Runner starts idling fast when engine is hot

Wow thanks for the update it is a V6 150 HP

 

[muskyone]

Re: Johnson 97 150 HP Ocean Runner starts idling fast when engine is hot

is it a carb or injected moter

 

[ecelani]

Re: Johnson 97 150 HP Ocean Runner starts idling fast when engine is hot

Muskyone, it is a carb, their <br />are 6 carbs since it is a six cyl.

 

[Reel Appeal]

Re: Johnson 97 150 HP Ocean Runner starts idling fast when engine is hot

Has the motor been serviced recently? Make sure there are no fuel leaks anywhere or any loose clamps/connections.Check for loose or detached vacuum lines.Check the primer solenoid (selector) and make sure the red pointer is down.You may need to get the Quickstart system tested.Check any component that has a engine temp. sensor/switch.Good luck.

 

[ecelani]

Re: Johnson 97 150 HP Ocean Runner starts idling fast when engine is hot

Thanks for your input, the engine is only serviced<br />during the winter for storage, then the plugs are replaced after the storage oil is blown thru the system. I checked for visual stuff, looks OK.<br />All carbs are pulling vacuum and all cylinders<br />are firing, pulled off plug wires and grounded<br />spark during rev up, no change. I can run the engine at 4000 rpm for 15 minutes and it is OK, this only happens when I run at 1500 rpm in a no wake zone and the engine is hot. The red pointer is down.