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Old 09-11-2018, 09:56 AM
rossi_the_heeler rossi_the_heeler is offline
TT Regular
Join Date: Aug 2017
Boat: 1994 Prostar 205
Location: midwest
Posts: 41
1994 Prostar 5.7 TBI Hot Start/Hard Start--SOLVED!--Finally!

Figured I needed to pay you guys/gals back for all your help and time over these last few months. I had some issues with hot stall/hard hot starts since I bought this boat a year ago. I installed a fuel pressure gauge port in the fuel line just before the fuel filter (got it on amazon) and was able to identify that I had a fuel pump going out. Thanks to mikeG205, I was able to cross ref a carter p-5000 from NAPA and that fixed my first issue which was fuel-related. (As JimN has reiterated a thousand times on this site...)
The second was, I would shut the motor off after a hard run, skiing or switching riders, messing with ropes, whatever...
And the motor wouldn't re-start.
I had spark, had fuel, no start.
Figured out that if I pulled the wires off of the ECT it would fire right up. Temp was probably around 165-170 ish.
I finally figured I had exhausted you guys enough, so I sent an email to Indmar.
15 minutes later, Larry Engelbert replied.--DAMN that's some GREAT customer service on a 20+ year old product. I AM IMPRESSED!
His words: "The 10 PSI fuel pressure on that engine is correct. The pressure is controlled by the regulator that is in the throttle body and 10 PSI is appropriate for that unit.

Your engine and EFI system was designed to run with a 143 degree thermostat. All of the fuel and timing curves in the ECM are adjusted to 143 degrees. If your engine has a problem with hot restart using the 160 but is OK with the 143 … use the 143. All of the Mastercraft TBI engines used the 143 degree thermostat from day 1 till the last engine was built."

So I swapped out the thermostat for a 143 and haven't had another issue since.
Thank you all for the help.
Hope this helps someone else on down the road!
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