Mercury 150 v6 water preasure 15lbs at idle

[oldmerc150]

Hi all, this is my first post. I have been working problems out of a used 150v6 i recently purchased.
The s/n on the lower end is a 1979 but the power head has been replaced so i can't tell what year it is.

Now to the problem, the guy I purchased the motor from said it needed a new water pump because he didn't have a full telltale stream at idle. I replaced the water pump and still only get a dribble. I checked the thermostats be heating water on the stove and they were fully open at 145'. I installed a pressure gauge in the 1/2" plug on top of the motor and I was shocked to see 15lbs at idle. From what I have read it should only be 2-4lbs at idle and around 15 at full speed. The dealer told me if water is coming out of the center of the prop the water pump is working. At idle with muffs I get enough water to get your hand wet in a couple of seconds.

Thanks for your help

 

[1nebel0]

Re: Mercury 150 v6 water preasure 15lbs at idle

That doesn't make sense...all my v-6's have just a couple of pounds at idle and around 12 or so at full throttle...these v6 motors pee very little and won't pee at all until the therms open up...keep us posted......

 

[BIGFLAT]

Re: Mercury 150 v6 water preasure 15lbs at idle

Just a thought... If you're doing your test with muffs, would the hose pressure cause the " supply " pressure to be greater that when you have the motor and boat in the water??? Could this cause the high idle pressure??? I'm having cooling / higher than usual temps on my V6 and read all post relating to them...BF

 

[Faztbullet]

Re: Mercury 150 v6 water preasure 15lbs at idle

From what I have read it should only be 2-4lbs at idle and around 15 at full speed.

Depends on year model and how routed...

 

[oldmerc150]

Re: Mercury 150 v6 water preasure 15lbs at idle

I am measuring the preasure at the top of head by removing the 1/2" pipe plug. I have checked thermostats by heartin up on stove in pan of water. They were fully oven around 140'. Could some thing be blocked causing the high preasure.

I did pinch the hose down and it didn't lower the preasure.

 

[Faztbullet]

Re: Mercury 150 v6 water preasure 15lbs at idle

Post a picture of poppet valve and t-stat hose routing

 

[oldmerc150]

Re: Mercury 150 v6 water preasure 15lbs at idle

Once I got it out on the water at full speed I got 15-20 lbs. At Idle I got 4-6. It must have been preasure from the water hose causing the high preasure.

Thanks for you help