Mini Jet Build

[Recoveringfiberglassaddic]

Running shallow in these rivers even with care fills the engine cooling water sand filter pretty often if ya hit a bar few times. I find myself cleaning it several times each outing. When the engine cover is built, I will not have the ability to casually look around and visually see the sand level. Will probably need to rig up some type of alarm so that when the water pressure drops to a certain pressure I am alerted and can clean the filter before waiting on the engine to overheat.

Any ideas? In a perfect world I would have some sort of sensor in the sand trap that would directly measure the level of solids in the bowl but all I have found so far seems to be fairly expensive ultra sonic sensors.

Anyone have the specs handy for min. water pressure at idle and WOT?

Can you post a pic of your sandtrap??

Jetboat Sandtraps – KLS Marine

This is what we run on the rivers around here. If you have yo adapt your plumbing and it's not what you are using I'd highly recommend it.

Only downside is it dumps the sand in the bilge, so you need to wash it out when you get home. Tilt the trailer and hose it out. Pretty minor work looking at what you've been doing to the boat.

 

[Weasel]

Found This thread which gives lot of good data! Not exactly my particular engine but can assume from that it would be hard the prevent a pressure alarm from false tripping at idle.

 

[Weasel]

Can you post a pic of your sandtrap??

Jetboat Sandtraps – KLS Marine

This is what we run on the rivers around here. If you have yo adapt your plumbing and it's not what you are using I'd highly recommend it.

Only downside is it dumps the sand in the bilge, so you need to wash it out when you get home. Tilt the trailer and hose it out. Pretty minor work looking at what you've been doing to the boat.

Not exactly the same but works the same way. You can see it in a few previous pictures.

 

[Weasel]

This project is still running slow motion.
Designing some type of skid plate or bars for protection of the controls and pump.

 

[Weasel]

Putting a skid plate under the pump.

Started trimming the back of the swim deck with round tubing. Will probably use the same thing to trim off the rear edge of the windshield. It's 0.750" with 0.035 wall so really thin and light weight.

 

[Speedling]

Very cool project man!

 

[Weasel]

Does anyone have experience extending the cooling water supply line? I would like to locate the sand trap up at the front seat so it can be monitored without opening the rear hatch.

 

[Speedling]

Does anyone have experience extending the cooling water supply line? I would like to locate the sand trap up at the front seat so it can be monitored without opening the rear hatch. View attachment 103133

It comes in through thr transom plate(s) via the white plastic screen and then goes into a rubber hose and a splitter which leads to exhaust and engine ports. If you were to lengthen it would cause a drop in pressure although less than if it was stuc with sand. You would want to lengthen straight fromthe inlet at the transom, loop back to the engine and the splitter.

 

[Weasel]

It comes in through thr transom plate(s) via the white plastic screen and then goes into a rubber hose and a splitter which leads to exhaust and engine ports. If you were to lengthen it would cause a drop in pressure although less than if it was stuc with sand. You would want to lengthen straight fromthe inlet at the transom, loop back to the engine and the splitter.

There would be a little pressure drop due to the additional surface friction of a longer hose. I could up size the line which would recover the lost pressure as long as the water velocity would stay high enough to keep the solids (sand) moving. Too large of a hose would let the sand fall out of the stream and settle in the lowest part of the hose but my guess is 3/4 in line would be fine. Will do a little reading on solid transfer within fluid flow.

 

[Speedling]

There would be a little pressure drop due to the additional surface friction of a longer hose. I could up size the line which would recover the lost pressure as long as the water velocity would stay high enough to keep the solids (sand) moving. Too large of a hose would let the sand fall out of the stream and settle in the lowest part of the hose but my guess is 3/4 in line would be fine. Will do a little reading on solid transfer within fluid flow.

And at different rpms you have different pressures as well. Would a filter at the back with a pressure gauge ran to the front serve the same purpose?

 

[Weasel]

And at different rpms you have different pressures as well.

I have considered a gauged but what type of baseline for pugged vs clean would you use since engine speed has so much to do with pressure?

 

[Speedling]

I have considered a gauged but what type of baseline for pugged vs clean would you use since engine speed has so much to do with pressure?

You would need to know pressure at different rpms and determine a minimum i guess. If i remember correctly the mercury sport jets of some models had something similar.

 

[Weasel]

You would need to know pressure at different rpms and determine a minimum i guess. If i remember correctly the mercury sport jets of some models had something similar.

If you look back at post 42 there is a link to some good information about the pressure vs RPM. It appears a pressure reading would only be useful if you operated consistently at a moderate engine speed or higher. Right now the plan is to size up to 5/8 in water hose at the transome and move the sand filter to the helm.

 

[Weasel]

Waiting for another aluminum shipment to finish the grab bars. In the meantime taking the old red primer off.

 

[Weasel]

Finished stripping the paint. Made few fuel tank fixtures.

 

[Weasel]

Engine cover/Rear seats are coming along. Sheet metal construction can be a bear.

 

[Weasel]

Paint has been ordered.....

 

[Weeb]

Getting there looks like it will be lots of fun.

 

[Weasel]

More sheet metal work. Paint is here but might be a while getting back on it. Full plate right now with other obligations.

 

[Jgorm]

Running shallow in these rivers even with care fills the engine cooling water sand filter pretty often if ya hit a bar few times. I find myself cleaning it several times each outing.

You might have a solution already but adding something like this would work great.

Rusco Spin Down Filter PE Screen T Style 1

The Rusco 1" Spin-Down Sediment Filter System with polyester filter screen makes solid particle removal simple and economical. The benefit of the 1" spin-down filter system is its ability to be cleaned and reused. The 1" spin-down sediment filter by Rusco has a clear cover that can be easily...

www.freshwatersystems.com