What's been done to this Promax??

[JCSmile]

So the fuel pressure drops to 37# when running on the hose. Should I raise it back up to 39 when running? Rich said that with the mods on this motor and these injectors that he would like to see it at 39 but I cant remember if that is running or just key ON pressure...

Disconnect the vaccuum line and see what it runs at. If I remember correctly, it should run a 39lbs engine off and drop a few psi at idle from the vaccuum reference. If you open the throttle it should rise back to ~39

[roadkill636]

Got the fuel pressure gauge on it tonite. When the engine is running it is at 39#s
When the vacume hose on the fuel psi regulater is pulled OFF it runs at 40#s.

How are these numbers? Rich said that I need to run a bit more psi than stock.

[Dave Strong]

Your fine they generally run 36 to 37psi stock at idle.

Dave

[roadkill636]

I got to finally run the Promax yesterday. Impressed with how much torque it seems to have in the mid range than my 2.4. Ran around for several hours. With a 27 pitch 4 blade ET style prop. Was running 1" above the pad and was hitting 7500 rpm and after a couple of miles it felt like it dropped a couple hundred rpms for a moment. It was almost dark and near the boat ramp. Could I have been running out of fuel with a VST? Plenty of fuel in the boat gas tank. But how many rpms can a Vst keep up with?

[Merc 2.5]

What boat did it go on ?

[Merc 2.5]

I just seen a viking. Cool hopefully u had a fuel issue

[Dave Strong]

I got to finally run the Promax yesterday. Impressed with how much torque it seems to have in the mid range than my 2.4. Ran around for several hours. With a 27 pitch 4 blade ET style prop. Was running 1" above the pad and was hitting 7500 rpm and after a couple of miles it felt like it dropped a couple hundred rpms for a moment. It was almost dark and near the boat ramp. Could I have been running out of fuel with a VST? Plenty of fuel in the boat gas tank. But how many rpms can a Vst keep up with?

You running the stock pulse fuel supply pump?

Dave

[roadkill636]

Yes. Stock pulse pump on mota.


How important is the check valve at the bottom of the Vst? Dont really see why a one way valve is even needed there. But mine is definitely bad. The rubber seal inside is all chewed up. And came rite out.

Not gunna do the 260 style fuel pump in boat this year.

[Dave Strong]

Thats for oil injection system, located on the bottom rear of the vst?

Dave

[roadkill636]

Yes fits into the bottom of Vst tank. Is it part of the oil injection system? That has been removed. Pre mixing now. . What's the purpose of this checkvalve?

[Dave Strong]

Yes fits into the bottom of Vst tank. Is it part of the oil injection system? That has been removed. Pre mixing now. . What's the purpose of this checkvalve?

To only allow oil into the vst tank and prevent fuel from backing up into the oil line. That fitting has a strange thread pitch so hard to find something to install as a plug. Merc did sell a plug may have the part number someplace.

Dave

Dave

[roadkill636]

I dont think we are thinking of the same part. This brass piece has NO threads anywhere on it. And it fits into the bottom of the Vst and the 1/2" fuel hose connects to it to the inlet of the ho electric fuel pump. That lil pink piece of rubber is what was inside of it tring to seal it but it's all ragged.

[Dave Strong]

I dont think we are thinking of the same part. This brass piece has NO threads anywhere on it. And it fits into the bottom of the Vst and the 1/2" fuel hose connects to it to the inlet of the ho electric fuel pump. That lil pink piece of rubber is what was inside of it tring to seal it but it's all ragged.

That part pushes into a brass fitting that is threaded into the vst correct?

Dave

[Dave Strong]

Number I found for the plug is 22-56800, probably has change up.

Dave

[roadkill636]

No threads anywhere part of this or the Vst tank. It pushes into the Vst and seals with the 2 Orings.
Part#31