Thread pitch help

[justfishintx]

I have a 1990 Evinrude 150 XP and I need to tap out the threads on the thermostats? Anyone know the thread pitch or the tap size?The head on the bolt is 7/16.I don't think it's stripped out I think it's just got some rust in the threads.Also I just put a new water pump on it and the thing pumped water like a champ for 5 minutes on the muffs then quit.Any thoughts?


Thanks
Chris

 

[MHBill]

Re: Thread pitch help

If its a 7/16 head then it is most likely 1/4-20 thread which is coarse. Fine thread is 1/4-28.

 

[justfishintx]

Re: Thread pitch help

Thanks it was a 1/4x20

Chris