Quick restrictor question

[Mike Grafas]

I've got a rn with b pipe, single cooling

Cooling from pump to manifold, head to bottom of headpipe, headpipe to T, straight part of T to fcv with 4mm restrictor after fcv

Right now I'm riding in 45degree water, only freestyle so no WOT

I started with a 6mm restrictor before pisser, then went to 3.5mm restrictor

Maybe I'm reading wrong but I would ride the ski on plane so I can stretch over the pole to the pisser and put a thermometer on water coming out of pisser

Both readings were about the same, 95-100 degrees despite restrictor

It seems like if I go to a 2mm it's not going to jump 20 degrees

Also I would imagine I should be hotter considering its water coming out of pipe

Now I'm worried about putting my ada head on with dual cooling thinking it's going to be WAYYY too cold

Btw my restrictor is a n/s seat drilled out and measured with a digital micrometer, been waiting for my jetworks quick connect restrictors for over a month now (backordered from blowsion)

 

[erik mx45]

dont check water temp check pipe temp !ride the ski stop pull hood quickly than check pipe mani temp and motor temp i used a rc temp gun ,
water will not give you a true reading to what motor temp is !

 

[Harbor]

Iam in 48 deg water with dual cooling and restricted to 2mm to get 140 ish cylinder head temp.... like
Eric said the pisser water is colder than the cylinder head/engine metal
Temps. So Measure the cylinder head temp with a gun or temp strips the way Eric said. Temp strips are more conventiant for me since they are always there and you can get a reading at any time. At 2mm I get water vapor coming off the pisser water which was a concern for me at first. I've since installed an onboard temp gauge to read my cylinder water temps while riding, I found out the water is colder than the metal. 140 head temp and 125 ish cylinder water temp. you might get into the 130 or 135 ish range with 2mm in 45 deg water.....

I've thought about going back to a parralel cooling system, one line y'ed to feed the engine and one to feed the pipe to get around this over cooling issue and having to restrict to so much but haven't done it yet.

Edit: since your running single cooling you might go 2.77mm first and get your temp then try 2.37mm and if needed then the 2mm. That's what I did on dual cooling, so with single you should to even more so, come in slowly on you target temp.

 

[Mike Grafas]

Alright perfect, I have temp strips but was waiting to install my ada head to put them on, next time I ride I'll take my infrared gun to the head and see what I've got, I have never had my pipe sizzle water yet so that could also be a factor, although they are not screwed far out at all

 

[tipafew]

Have been riding 25 years in cold water and never cold seized a motor and run my motors a long time between rebuilds. Some of those years I tried to pay attention to engine/water temps. Most of the years I haven't and neither do the guys I ride with. Yes, it's better to have it at the right temp but don't get to crazy obsessed about it as long as you are running a fairly mild set up and no WOT runs. The only reason I even think about engine temp is because I want my handwarmers to be warm.

 

[Mike Grafas]

Another quick question

I have installed my ada head but now am a little confused on where to put the restrictor

On my single cooling set up I had pump to mani, head to bottom of pipe, top of pipe to pisser. Restrictor after y to pisser, fcv and 3mm in stinger

NOW with dual cooling I will obviously restrict head to pisser BUT do I put my second restrictor on my head outlet BEFORE my pipe? (Kind of makes sense but then pipe won't be restricted or have pressure)
OR do I put second restrictor before pisser after y like I had it with single cooling? (This seems to make more sense to me so pipe still has pressure)

I have seen it with the restrictor right after head outlet but don't see any benefit to it

 

[Harbor]

2 restricters at the pissers, I put the 3rd stinger restricter after the fcv @ the stinger so I can adjust when flow occurs thru that restricter...

also Thought about it the other way, 3rd restricter right before the fcv to lower the pressure on the valve, but haven't tried it that way

 

[Mike Grafas]

2 restricters at the pissers, I put the 3rd stinger restricter after the fcv @ the stinger so I can adjust when flow occurs thru that restricter...

also Thought about it the other way, 3rd restricter right before the fcv to lower the pressure on the valve, but haven't tried it that way

Ok great, just wanted to make sure I was thinking of it right

After I saw the picture of the restrictor before the pipe it got me thinking, thanks for the quick response

 

[Mike Grafas]

Ok so I just got out of the water, about 45 degree temp

New ada head, dual cooling, I had two 3mm restrictors before both bypass fittings

Rode slowly until up to temp then checked temp stickers on head, head was about 95 degrees. Only had one 2mm restrictor so I put that in the bypass direct from head (other one goes to bottom of pipe)

Cylinder still around 95-105

Well if I put another 2mm in place of the current 3mm I doubt I'll be getting head temp up to 120-130

I've never heard of a 1mm restrictor before but I'm thinking of going for it

Is there anyone against going to a 1mm restrictor in both bypass fittings??

(Head temp was colder than single cooling stock head which makes sense obviously, also chamber never even got to 140 degrees when I think 220 is sizzling point)

 

[Quinc]

You might try these:
https://www.amazon.com/gp/product/B0026PU6GK/ref=ox_sc_sfl_title_1?ie=UTF8&psc=1&smid=A1T1R9Q3ML5YGI

Or better yet, someone find a 3/8" inline thermostat

 

[Mike Grafas]

You might try these:
https://www.amazon.com/gp/product/B0026PU6GK/ref=ox_sc_sfl_title_1?ie=UTF8&psc=1&smid=A1T1R9Q3ML5YGI

Or better yet, someone find a 3/8" inline thermostat

I have some brass plugs I can drill to 1mm, just never heard of anyone ever having to go that small

 

[Harbor]

Use (3) 2mm restricters... so the water cant just flow out thru that 3mm, it needs to stay in the engine longer to warm it up... that should get you warm enough to around 120 125 ish..

If you only get to 115 or 110
That's fine stop
Their with the 2mm restricters....

Yes Iam against 1mm, 2mm is the smallest you should need.. 2mm is alarmingly small imo...

In colder water you won't start seeing a temp change until (3) restricters of the same size are used... 2.77 or 2.37 or 2.0 all these will give a slight temp rise.

At that water temp of 45 you should be ok at (3) 2mm restricters

It will be warm enough, I'd stop their....

If you insist on going smaller after youve tried the (3) 2mm restricters then drop one drill size and drill out three new restricters.. the next bit down is 1/16 or 1.68mm

With the restricters the water pressure rises in the engine and pipe. So I've blown off a cooling line at the bulkhead a few times because of this. Now I keep with me hose clamps and a tool to tighten clamp and zip tie if all else fails and needle noise to remove restricters if needed...

With the increased pressure you'll have to adjust your pipe adjusters too lessen the spray at the higher pressure...

Also keep an eye on your pissers spray patterns and flow.. I got a small grass blade in one of mine and it changed the spray pattern..
also the first time a line blew off, my engine was at 168 when I noticed it and got the hood off. Clamp was gone but I had those twisty rubber coated wire things they sell at the hardware store on board, so used one as a temporary clamp and limped it to the boat dock..

I check clamp torque regularly now, all clamps!

With all this it seemed more of a hastle and a large risk to my engine to be worth doing. But I carefully did it anyways and so far so good, just takes some awareness I guess...

Hope this helps you

Edit: I should ad that fuel cools the engine, I had my rear cylinder 14 deg colder than the front. Tried staggered restricters like you have with no change. Turned out it was the idle circuit on the cylinder that ran cooler. 1/2 turn out on the low screw was not flowing the same amount of fuel thru each carb.. had to lean that one out till the cylinder temps were close, plug also had wet fuel on it btw...

 

[Mike Grafas]

Use (3) 2mm restricters... so the water cant just flow out thru that 3mm, it needs to stay in the engine longer to warm it up... that should get you warm enough to around 120 125 ish..

If you only get to 115 or 110
That's fine stop
Their with the 2mm restricters....

Yes Iam against 1mm, 2mm is the smallest you should need.. 2mm is alarmingly small imo...

In colder water you won't start seeing a temp change until (3) restricters of the same size are used... 2.77 or 2.37 or 2.0 all these will give a slight temp rise.

At that water temp of 45 you should be ok at (3) 2mm restricters

It will be warm enough, I'd stop their....

If you insist on going smaller after youve tried the (3) 2mm restricters then drop one drill size and drill out three new restricters.. the next bit down is 1/16 or 1.68mm

With the restricters the water pressure rises in the engine and pipe. So I've blown off a cooling line at the bulkhead a few times because of this. Now I keep with me hose clamps and a tool to tighten clamp and zip tie if all else fails and needle noise to remove restricters if needed...

With the increased pressure you'll have to adjust your pipe adjusters too lessen the spray at the higher pressure...

Also keep an eye on your pissers spray patterns and flow.. I got a small grass blade in one of mine and it changed the spray pattern..
also the first time a line blew off, my engine was at 168 when I noticed it and got the hood off. Clamp was gone but I had those twisty rubber coated wire things they sell at the hardware store on board, so used one as a temporary clamp and limped it to the boat dock..

I check clamp torque regularly now, all clamps!

With all this it seemed more of a hastle and a large risk to my engine to be worth doing. But I carefully did it anyways and so far so good, just takes some awareness I guess...

Hope this helps you

Edit: I should ad that fuel cools the engine, I had my rear cylinder 14 deg colder than the front. Tried staggered restricters like you have with no change. Turned out it was the idle circuit on the cylinder that ran cooler. 1/2 turn out on the low screw was not flowing the same amount of fuel thru each carb.. had to lean that one out till the cylinder temps were close, plug also had wet fuel on it btw...

That's some good info their, and yes by 1mm I meant 1.5mm with a digital micrometer

I should also add I have ball valves before my manifold on both lines coming in (for towing reasons)

Would it be better to go to 3mm restrictors (go larger for clogging reasons) and close my valves a bit to regulate flow coming in?

 

[Harbor]

(Restricters) I would encourage you to continue to use used needle seats or if making your own, have the restriction bore not be any longer than a drilled seat and add the larger needle bore to it as well. I have the water flow in on the drilled side and exit the needle bore size so the needle bore doesn't act like a catch for Debi. Also easy to grab with small needle nose pliers.. I say make them the same so you don't get a variance in restriction and cooling from some other length bore or design.....

Year round iam only using three sizes, 2.77 2.37 or 2.0 and an adjustment from season to season is simple and predictable. Also with them installed at the pissers it's easy to visually see if I've got an issue....

Adjusting your ball valves, I don't know howed you repeat the adjustment thru the different seasons or for a different lakes water temp.

I'd suggest leaving the ball valves wide open and use restricters.
Right now it's winter so it's good your about to find your winter cold water restricter size. I saw no temp drop from 5mm all the way to 3mm.... In 65 deg ish water temp didn't start to rise till I used a 2.77

Soon it will be spring then summer, if water is warmer than 65 you'll prolly be 2.77 or 3.0 or larger...

Ball valves at the pissers and before the stinger could work, too much adjusting though.. Seats are simple, easy to install and get a predictable result every time...

I've never clogged one, just a blade of grass, still plenty of flow just changed the pattern and the sound...

At 2mm on all three in 45 deg water with cold air you should see water vapor coming of the pisser water. I do at 48/50 ish water.
Iam pretty sure at 1.68 you will for sure....I see vapor at 120 to 125 deg pisser water temp with a cylinder temp of 140 ish to 149 range...

Jetmaniac or other vendors have used seats too if that helps

 

[Mike Grafas]

(Restricters) I would encourage you to continue to use used needle seats or if making your own, have the restriction bore not be any longer than a drilled seat and add the larger needle bore to it as well. I have the water flow in on the drilled side and exit the needle bore size so the needle bore doesn't act like a catch for Debi. Also easy to grab with small needle nose pliers.. I say make them the same so you don't get a variance in restriction and cooling from some other length bore or design.....

Year round iam only using three sizes, 2.77 2.37 or 2.0 and an adjustment from season to season is simple and predictable. Also with them installed at the pissers it's easy to visually see if I've got an issue....

Adjusting your ball valves, I don't know howed you repeat the adjustment thru the different seasons or for a different lakes water temp.

I'd suggest leaving the ball valves wide open and use restricters.
Right now it's winter so it's good your about to find your winter cold water restricter size. I saw no temp drop from 5mm all the way to 3mm.... In 65 deg ish water temp didn't start to rise till I used a 2.77

Soon it will be spring then summer, if water is warmer than 65 you'll prolly be 2.77 or 3.0 or larger...

Ball valves at the pissers and before the stinger could work, too much adjusting though.. Seats are simple, easy to install and get a predictable result every time...

I've never clogged one, just a blade of grass, still plenty of flow just changed the pattern and the sound...

At 2mm on all three in 45 deg water with cold air you should see water vapor coming of the pisser water. I do at 48/50 ish water.
Iam pretty sure at 1.68 you will for sure....I see vapor at 120 to 125 deg pisser water temp with a cylinder temp of 140 ish to 149 range...

Jetmaniac or other vendors have used seats too if that helps

Well right now the water is 45 degrees and with 2mm restrictors in both bypass and a 4mm in stinger my head temp never got over 100 degrees.

And I started using needle seats but went to 1/8 npt brass plug grinded down to fit

What did you mean by 3 - 2mm restrictors, i have both lines from pump to manifold, then one from head to bypass and other from head to pipe, then out of pipe to bypass/fcv. I've seen a lot of people saying they have had 2mm restrictors with dual cooling and are fine and up to temp but I am wayyyy to cold, I think my 2mm restrictors measured to 1.90mm actually

Doesn't it seem odd that with 2 - 2mm restrictors I am only at 95 degrees

I'm also not going past 1/2 throttle or cruising, I'm slowly warming it up at 1/4 throttle and then maybe half throttle then checking temp, can't seem to figure out why temp won't rise up with 2mm

 

[Harbor]

^^^ wasn't aware of this, I guess you did some more adjusting testing, cause your info in post #9 is different as far as restricter sizes and where they were placed......or Iam reading it wrong, which is intirly possible lol, no problem

What I mean by (3) is we want all 3 restricters the same size..

You've made your own that's cool, lets do this next...and re-test

Please install (3) 2mm restricters so the hole system is restricted the same and water can't bypass and still flow thru one larger restricter in the system somewhere..

When you ride the ski for the test, ride as you normally would, ride so the engine builds it heat as it normally would when you ride.

Ill say no wide open runs longer than 3 seconds or so and no bouy riding or racing... ride it hard though like you normally would and check your temps.

Let's see where we're at then and go from there.

Side note; This b-piped ski I have here got rich over the winter vs summer and had to be leaned out cause it was blubbering. This is not the ski with one cylinder cooler than the other that's a different ski. Not sure why maybe it was too rich already or the fuel temp
In the tank is condensing the fuel. It's been broke in for 31 hours... last break
In I did I found after break in that my engine was too too rich and had to be leaned out. But I noticed that one after the second tank... this b-piped ski is not mine I guess the owner may not have noticed it like I noticed mine...

 

[Mike Grafas]

^^^ wasn't aware of this, I guess you did some more adjusting testing, cause your info in post #9 is different as far as restricter sizes and where they were placed......or Iam reading it wrong, which is intirly possible lol, no problem

What I mean by (3) is we want all 3 restricters the same size..

You've made your own that's cool, lets do this next...and re-test

Please install (3) 2mm restricters so the hole system is restricted the same and water can't bypass and still flow thru one larger restricter in the system somewhere..

When you ride the ski for the test, ride as you normally would, ride so the engine builds it heat as it normally would when you ride.

Ill say no wide open runs longer than 3 seconds or so and no bouy riding or racing... ride it hard though like you normally would and check your temps.

Let's see where we're at then and go from there.

Side note; This b-piped ski I have here got rich over the winter vs summer and had to be leaned out cause it was blubbering. This is not the ski with one cylinder cooler than the other that's a different ski. Not sure why maybe it was too rich already or the fuel temp
In the tank is condensing the fuel. It's been broke in for 31 hours... last break
In I did I found after break in that my engine was too too rich and had to be leaned out. But I noticed that one after the second tank... this b-piped ski is not mine I guess the owner may not have noticed it like I noticed mine...

I will do that today, I guess I have to pull my restrictor in my stinger (I believe it is a 4mm)

But even with a flow control valve set at 1/4 throttle opening and 2 - 2mm restrictors shouldn't I still be getting up to temp even riding slow?

I only ride freestyle, basically just tricks, set up wakes, subs etc, so no cruising around for me but I still figure it should get up to temp riding like this or else I'd never be able to open the throttle up

If the 3 - 2mm restrictors (before both bypasses and after fcv) still don't get up to temp should i restrict before the manifold?
I have 2 ball valves there that I can easily close up slightly, or should I stay away from restricting the incoming water?

 

[Harbor]

Your normal ride style is great, same as me.... ride it like that, ride it hard no sissy footing it for the test....

Let's see where your temp is after this test... with (3) 2 mm restricters....

We'll go from there after you report...

Might have to go (3) 1.68 restricters next...

May I ask how many temp strips are on your engine and where ?

I'd leave the ball valves alone personally

 

[Mike Grafas]

Your normal ride style is great, same as me.... ride it like that, ride it hard no sissy footing it for the test....

Let's see where your temp is after this test... with (3) 2 mm restricters....

We'll go from there after you report...

Might have to go (3) 1.68 restricters next...

May I ask how many temp strips are on your engine and where ?

I'd leave the ball valves alone personally

I agree, I'd rather not restrict the incoming water

And I've got 2 on the head, one on the pipe and one on the chamber in front of the coupler (see pic)

I will definitely report back after I test everything, but also looking at a 1.50mm restrictor it gets me worried with out small it is, even a piece of sand could clog it up, so I'd like to stay upwards of 2mm

 

[Mike Grafas]

Your normal ride style is great, same as me.... ride it like that, ride it hard no sissy footing it for the test....

Let's see where your temp is after this test... with (3) 2 mm restricters....

We'll go from there after you report...

Might have to go (3) 1.68 restricters next...

May I ask how many temp strips are on your engine and where ?

I'd leave the ball valves alone personally

So harbor I tested it, just got out of the water and what do you know, it was the stinger restrictor all along.

I thought about it before riding and if I'm restricted 2mm but after fcv is 4mm (actually measured to 4.38mm) then when fcv opens water is going to exhaust more than it is bypass

I rode around and check, then rode hard and checked and both times I was at about 113 to 122 degrees as opposed to the 95 degrees I was at originally

That's a 20 degrees jump just from my restrictor after my fcv

I must have read wrong but I thought I saw that factory pipe recommends a 4mm restrictor before stinger all the time, now I know that I have to restrict all 3 every time I change

Thank you again for helping me figure this out, I could probably go to 1.77mm if I wanted to but I'm happy the way it is running now