Mercury "racing" Trim Pumps

**Krazymaan** · 04-09-2018, 09:49 AM

Just looking for info
two yrs ago now. I removed my regular mercury V6 trim pump motor and reservoir and replaced it with a mercury racing trim pump and reservoir because the old one seemed slow to me. to my surprise the mercury racing trim pump was no faster than the original one. If it was faster, maybe 10%. So whats the purpose of having a "racing" pump thats no faster than a regular one. Thats a lot of money for a sticker.
For a comparison I can take my 1987 OMC XP 200 put it next to the Merc V6 with the racing pump and by the time the mercury just goes from bottom to top, The OMC went up down up and down. I was at least expecting that level of performance.

**CUDA** · 04-09-2018, 04:59 PM

Real racers know how to change the pressure , even in the BoB's unit
Look at the bright side !
You got a cool sticker ...
I bet my Bobs is faster then you $$ one

**dwilfong** · 04-09-2018, 06:38 PM

pressure has nothing to do with how fast it is.
Her you go every thing you think you know.
https://www.parker.com/literature/Hy...%2012-2015.pdf

**WillySteve** · 04-09-2018, 06:43 PM

I've used a Mercruiser pump for years. Because of it's wider gears, higher volume and pressure, it rocks!
If hat's not fast enough then run it on 24v!!
I've never timed mine but would say it goes from full IN to full UP in about 4 seconds!

**patchesII** · 04-09-2018, 06:48 PM

There are different Mercury "Racing" pumps. Some are faster than others

**boaterok** · 04-09-2018, 06:49 PM

Originally Posted by dwilfong

pressure has nothing to do with how fast it is.
Her you go every thing you think you know.
https://www.parker.com/literature/Hy...%2012-2015.pdf

Way more information than I need to know at my stage in life.

**WillySteve** · 04-09-2018, 06:55 PM

Originally Posted by dwilfong

pressure has nothing to do with how fast it is.
Her you go every thing you think you know.
https://www.parker.com/literature/Hy...%2012-2015.pdf

I beg to differ!!!
The higher the pressure of any hydraulic system's master or pump, the faster it will move it's slave....as long as the volume is available to keep the master from running out of supply fluid.
A trim pump is moving x amount of fluid into x amount of cylinder space. the Higher the pressure of the pump, the faster it will fill the x space in the cylinder.
Fill a 5 gallon bucket with water at a trickle and then at full water pressure!

**texasvector** · 04-09-2018, 07:14 PM

the faster pump is actually lower psi.....high volume -low psi is the fast mercruiser pump.

the slow factory pump is low volume- high psi

**WillySteve** · 04-09-2018, 07:29 PM

Mercruiser pumps are and always have been set at a higher pressure than outboard pumps. It true that volume is what fills the cylinder but a higher pressure moves the volume at a faster rate!
Pressure has all to do with it!!!
For example, how fast would the trim cylinder raise at say 5 psi compared to 1500 psi!

**dwilfong** · 04-09-2018, 07:41 PM

It is full flow not full pressure. a orifice will make higher pressure with the same flow. when you turn the knob on you bucket fill idea it increases flow witch will produce more pressure in the hose. pressure is a product of flow. flow is volume. dose not matter what the pressure is with the same volume it will move the same speed.
How do you get more flow ? Higher pump speed or larger pump gears.
How much pressure dose it take to move a trim cylinder under full load?
Lets say it takes 1000 psi. now no mater how high you set the pressure it will only produce 1000 psi in the system. So if you are set higher on the relief than 1000 psi it will not return any fluid to the tank. so you get full FLOW from the pump.
The only time higher pressure settings will make it faster is if thy are set lower than the operating pressure of the cylinder to move the eng under full load and the relief dumps oil back to tank.
How many have ever checked the system PSI when the eng was pulling wide open and you are trimming up?
bottoming out the cylinder will only tell you the relief setting. not what the operating under moving load pressure is.
I have worked on hydraulic systems for 35+ year. Have a good idea what I am talking about.
Hydraulic lesson for the day.........................

**CUDA** · 04-09-2018, 07:46 PM

Yeah all drag racers use 24v for start and trim , unless you run a 150psi class you better use 12 to crank / check pressure

Some use 36v,
somehow low voltage will kill a starter but they eat high volts with ease.

If you want 24 to start and trim you just need a small bat to get it flying, amps not that important volts.

**WillySteve** · 04-09-2018, 07:51 PM

Take a trim pump ran on 12v as intended and run it on 24v. The motor rpm will come up which will move more volume at a faster rate, raising the cyl at a faster rate....pressure stays the same.
This is because the output volume of the pump has increased.
A pump can only produce whatever pressure the regulator valve is set on.

However take that same pump and increase it's pressure. It will move more volume because of the higher pressure which will move the cyl. at a faster rate!
A mercruiser pump has both higher volume because of it's wider pump gears, plus runs at a higher pressure.....best of both Worlds!!!

**WillySteve** · 04-09-2018, 07:56 PM

I also have worked on Hydraulic systems, but for over 50 years....I also know what I'm talking about!
You raise the bypass pressure on a trim pump and see if it doesn't move faster....regardless of the gear size!