Super high intake pressure??????

**525SC777** · 04-20-2012, 10:56 PM

Boat running dry and real loose but at wot I'm seeing 60lbs of intake pressure and if I let off the gas suddenly the boat wants to hook to the left feels little tense at high 80's low 90's we have fought with this boat for years ie: spooned bottom, shoes, ride plate angles, various wedges to get the nose out of the water and get the boat to run dry has a lot of horsepower now and now I got the boat up on the spoon and it's super fast but I'm really worried about sudden lose of power and getting pitched!!!!!!

**BIG JOHNSON** · 04-20-2012, 10:59 PM

Wish I had this problem with my jet bote

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**widowmaker** · 04-20-2012, 11:29 PM

What type of boat?

**NO REGRET$** · 04-20-2012, 11:50 PM

Originally Posted by widowmaker

What type of boat?

sounds like a V BOTTOM l ...?????

**525SC777** · 04-21-2012, 08:01 AM

1977 Blanchard only 2 ever made.

**1/4 Miler** · 04-21-2012, 08:28 AM

What size nozzle insert are you running and have you tried using incrementally larger inserts to see if that will lower the intake psi? Also what's the location of the psi sensor on the intake?

**525SC777** · 04-21-2012, 08:41 AM

Standard place diverter and droop can't inner change nozzle inserts. Reading pressure from thermostat housing.

**RIVER4FUN** · 04-21-2012, 09:18 AM

Originally Posted by 525SC777

Standard place diverter and droop can't inner change nozzle inserts. Reading pressure from thermostat housing.

Huh?

**CarbonMonoxide** · 04-21-2012, 09:26 AM

Might be a reason there are only two.
Speed limitations might be one of them, handling characteristics might be another, or both. You may have reached the limits of the hull. Safety has to take over at some point. Just because you can add a 1200 hp motor, doesn't mean you should.
Have you tried cutting back the runners on the loader? Closing the mouth on the shoe?

**sdpm** · 04-21-2012, 09:55 AM

Originally Posted by RIVER4FUN

Huh?

I think his problem has to do with his mufflers! Too much back pressure!

**ap67et10** · 04-21-2012, 10:14 AM

You first need to use the search feature and look for all the different threads on correctly tapping the suction housing on the JET. Then you need to search for cooling system setup to figure out how to reduce your water pressure in the engine. I know people talk about intake pressure, but that's not referring to your intake manifold on the engine when they are concerned with shut down issues at speed. They are two completely different topics and could possibly be the two most popular and well documented topics on this forum. Just read up and you'll get the boat worked out. Btw it look like clean boat!

AP

**GRoper** · 04-21-2012, 10:54 AM

I may be wrong but I wouldn't think intake manifold pressure would have anything to do with shut down issues.

**525SC777** · 04-21-2012, 11:12 AM

Well i have always heard that your block pressure is related to how good or bad your pump is loading? Too much block pressure ie: 60lbs could cause head gasket issues? I have cometics so they should hold up? I thought you wanted to stay around 20lbs intake pressure? Looking for good advice not some douch talking bout mufflers???

**snoc653** · 04-21-2012, 11:53 AM

Originally Posted by 525SC777

Well i have always heard that your block pressure is related to how good or bad your pump is loading? Too much block pressure ie: 60lbs could cause head gasket issues? I have cometics so they should hold up? I thought you wanted to stay around 20lbs intake pressure? Looking for good advice not some douch talking bout mufflers???

The pressure on the intake manifold should be controled by a gate valve coming off the pump or a pressure releif valve. It really has nothing to do with how your pump is or isn't loading in the big picture of things. When they are talking intake pressure they are referring to the pressure on the pump intake. If it is too high the jet pump isn't pushing the water through fast enough and you are building pressure under the boat which could be lifting the tail. Racers wanting to insure their pumps are staying loaded monitor the intake pressure of the pump. They also will usually monitor or log the pressure in the bowl as well. Too much pressure in either of the pump locations mean bad things could happen. Both pump location pressures are well documented on the forum.

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Super high intake pressure??????

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