77 70 hp off and on weak tell tail

[txbandit44]

ok replaced the water pump and updated the housing to the plastic one with the metal cup becuase i didnt have any water comming out of any where it should have been. Prop hub or exhaust ports. I added a tell tale and dropped it in that lake yesterday and the new tell tale is working great. I ran around checking timming and linkage made a few WOT passes and look back and the telltale is just dribbling at idle. I throttle up and it improves a bit but not near what it should be. I stopped the motor pulled the cowling to check for obvious issues none found. Replaced cowling started it and still has the same issue. i do have alot of water comming from the exhaust relief ports so i know im getting water to the motor.

I stopped and fished for about 15 maybe 20 min and started the motor again. Back to a good solid stream ran about a mile at half throttle and it started getting week again. Fished for about an hour and started it again the stream was strong and then got weak after about a 15 min ride back to the ramp


What would cause this. i was thinking cavitation in the pump itself but I have such good flow from the exhaust I dont think its at the pump. And I have a clear tube for the tell tail and i dont see any bubbles inthe line while its running

I installed the tell tail in the block see the pic in this thread http://forums.iboats.com/showthread.php?t=288283
It worked great last time i did it

 

[boobie]

Re: 77 70 hp off and on weak tell tail

Have you got any dirt in the tell tale line or the fitting itself ??

 

[txbandit44]

Re: 77 70 hp off and on weak tell tail

The tell tail fittings are new and the line is clear plastic tube. Could the t-stat be opening when it gets hot and reducing the pressure in the #1 cyl jacket?