Bass boat 1999 Javelin Renegade 19 (18'9")
prop to pad 3.25"
When I repowered in 2014 I recall my dealer telling me to make sure my water pressure stays around 23-25 psi when above 4500 rpm. All was good for the first few years. At my 3 year service they changed my water pump and everything was still good until late last fall. That's when I noticed my water pressure would fall from 25 to 10 psi when I was in a turn. In a straight line it would be 22- 24 which is very close to what its suppose to be. Unfortunately my dealer sold his shop and relocated to another state so this is why I am seeking advice here.
Around mid April I personally installed a new water pump kit. There should be a post on here where I got advise. My water pump had around 130 hours at 3 years if my memory is correct and 187 hours the 2nd time it was changed when the motor was 4.5 years old. A new water pump kit did not resolve my issue when I changed it a few months ago. When I am in a long sweeping turn if I back off the throttle and bump the trim down my pressure comes back up. I know this may sound strange but sometimes in a turn I can slightly move the steering wheel back and forth and it will gain pressure.
Anyways I also installed a ICOMMAND gauge early 2019. Every since the gauge was installed my typical idle temperature was around 160 ish. Running down the lake cruising or at wide open throttle it was around 165-173. Two times I had my hot alarm go off when the temperature on my gauge was only in the upper 160's but both times I was in a long sweeping turn and I forgot to pay attention to my water pressure. Both times I instantly shut down and restarted the motor and the hot light went out.
They make 4 sizes of water pickups for my motor. It came with flush mount. The other three sizes are .060, .160, and .410 so I install the largest ones. It made a HUGE difference in my water pressure and the operating temperature of my motor. Now I have 30 psi @ 4500 and right before I trim up onto the last step of the pad @ 5000 it will actually reach 36 psi. I can make hard turns and my pressure will not fall below 25 psi. Also when cruising or running hard my operating temperature is 138* when it was upper 160-173*
So I guess my questions are...(and don't think these are stupid questions because I really don't know) but is there a such thing as having too much water pressure? Also is my operating temperature to low?
The reason I ask is because I don't want to cause harm by having too much pressure if there is such a thing. Plus I know two stroke motors need to run hot enough to burn carbon so I want to make sure I am running hot enough. I know a stuck open thermostat can cause carbon build up by not letting the motor get up to operating temperature so that's why I ask that question. FYI I run nothing but XD100 and use 2+4 in every tank. I also run Carbon Guard in my fuel twice per year. One full tank in the spring and one full tank in the fall.
Looking back there is only one thing I done that could impact my water pressure. I did not think of it until I was typing this up but my issue started when I installed a sidescan/downscan transducer on my jackplate last fall. It's on the starboard side of my jackplate and at least 10-12" higher than my water intake screens. I don't think this is the issue because I would lose pressure even if I was turning port and the transducer is mounted on the starboard side. Maybe I am overthinking it or maybe it is just a coincidence or maybey it is my real problem. Anyways sorry for such a long post. I had rather give too much info and have whats not needed filtered out than to not give enough info...so long story short...is my water pressure too high and is my operating temp too low... please advise
Your symptoms describe the effects of an object that is disrupting clean water flow into the motor. The gearcase inlet screens are ingesting aerated water in a turn. It probably affects one way more than the other. The quickest way to tell is to temporarily remove the transducer and lay it in the transom well and go for a test run.
Be sure there are no protrusions or fittings on the transom or hull within 17" of the center of the motor.
"There is never just one thing wrong with a boat";
-- Travis McGee, main character in a book series by John D. McDonald
The factory recommends that a properly trained technician service your Johnson or Evinrude outboard motor. Should you elect to perform repairs yourself, use caution, common sense, and observe safety procedures in the vicinity of flammable liquids, around moving parts, near high-temperature components, and working with electrical or ignition systems.
The information offered here is only general in nature and should not be construed as complete factory approved procedures, techniques, or specifications. Always use the proper service manual for your motor, up-to-date service literature, the correct tools, and have an understanding of how to proceed with troubleshooting and repair methods. If you are unsure or uncomfortable with a procedure, a situation, or a technique, enlist the services of a factory trained technician.
Thanks for the comments. In the future I will drop down from the .410 inlets to the .160 That seems like a big drop considering the next size below the .160 is .060... Anyways out of curiosity what is the reccommended water pressure for 4500 and above rpm. Also what is the reccommended temperature for 4500 and above rpm.
There are 4 size of water screens for my motor. I have ran 3 of the 4 sizes.
Flush..losing pressure in the turns and falls to 10 psi. I had a couple hot alarms when making long sweeping turns. When running in a straight line 22 psi @ 5000 or above. Idle temp 155-160*. Running on pad 160-170 with occasional low 170's.
.410 Has excellent water pressure. In fact it was so strong I came here asking if it was too much pressure because my running temperature dropped 30-35* Above 5000 rpm I saw 36 psi and my engine operating temperature was 135*...now take this into account. I only ran the boat twice with this screen and both trips I never had any long runs where I pushed it hard for any lenght of time. I only opened it up for a 1/2-1 mile just to watch my numbers.
Installed .160 and pressure went down but it's actually where I think it needs to be but I still have some concern with my operating temperature. First the pressure...23-25 above 5000 with it bumping 27 at the right trim angle. When I turn the steering wheel I lose little to no pressure. I made several turns at 4000-5000 and the pressure either held strong or fell 2-3 psi so I am happy with the pressure. As for the temperature idle is 155-160* with all screens. Running around I typically cruse at 4000-4500 and my operating temperature is 135-140*. I had one stretch where I let it eat and ran 5600 for about a mile and the temperature climbed to 160* and held 25 psi.
I looked at my 3 year check up print out and the profile shows my motor spent a lot of its life running in the 160-170* range. To my surprise a there is a lot more time at 1000 rpm or less than what I expected. My engine idle temperature has always been 158-160* so I guess this explains the higher than what I expected time above 160* I guess idling in and out of places adds up more time than what I thought. My local lake is only 7000 acres so it's not like I make continuously long runs above 5000 very often. All of the information on my 3 year print out was when I had the factory flush screens. Looking at the chart that Hi_c posted I am dead on with my water pressure. Rickmdc53 recommended that I step down a screen size to get mt temperature close to 145*. I stepped down in size and got my pressure perfect but the rpm I cruise at the most (4000-4500) still has 135* engine temperature with either the .410 or .160 screens.
I guess my question is there a chart that shows recommended engine operating temperature at particular rpms. I do not want to run too cold beacsue I know that can lead to carbon build up. Maybe I am overthinking this...please advise.
09-04-2019 03:45 - edited 09-04-2019 03:52
good question about the normal opperating temps as i dont have a water pressure gauge or the (I) what ever its called thing only a RPM with the 4 warning lights under it and a nmea hooked up to my garmin that gives me a couple things like temp,RPM, fuel used. My new G2 200ho idles around (temp)150 and when crusing about 3500 RPM i have seen it close to 170. The water temp in S Florida has been warm.