Water preasure gauge necessary

[dan2116]

Hello everyone. I have just ordered my first time for real bass boat to me anyway ( Ranger RT 178 w/ 75hp Four Stroke Merc ) and have a question if a water pressure gauge for the engine is necessary. Is it possible to over trim and lose pressure and not realize it till it causes a serious problem or losing pressure for some other reason. My dealer did not seem to think it was a absolute must have but I would rather be safe than sorry.

Is the installation of the gauge a difficult thing to do ( to the motor , routing and mounting ) ?

[KP1923]

With the newer, more reliable engines, I personally do not have one, nor see the immediate need to get one. By gaining experience on the water, you will know it if you "overtrim" an outboard.

FYI, a water pressure gauge does NOT warn against overheating. It warns against a water pump impeller going bad that may LEAD to an overheat. Overheats are not always due to lack of pressure. Stuck thermostats, engine timing, lean carburetor are other reasons. Outboards typically have an overheat buzzer that warns of overheat. If overheat is what you are interested in then a TEMPERATURE gauge is what you are after. Typical racing boats have both gauges because they monitor two very different situations. If you are still stuck on a pressure gauge, some engines can have them plumbed into the tell-tale and will work fine. Others do not. The idea is to install a new impeller when you install the gauge. You then note the idle, mid-range, and wide open throttle pressure readings. If those number change significantly you know it is time to service the impeller again. I just replaced my impeller on my 2015 Yamaha 115 four stroke, and the one I took out, in terms of wear, looked just like the new one I put in.

Your mileage may vary, but for me personally, I choose to spend the $$ elsewhere. Others here may have a different opinion......

[bshort]

The 75 does not have a wp sending unit. You'll have to get one installed.

[dan2116]

OK. Thanks. I won't worry about it then. Just keep up on the maintenance for sure.

[Casslaw]

If you install a jackplate the answer would be a definite yes but as rigged from the factory I doubt you will habe wayer pressure issues unless you run in lakes full of weeds! Blew my little 20 Mercury that way when I was a kid, I still remember it slowing down as it locked up

[Rick H]

IMHO Yes!

[Jeff Hahn]

No, it’s not absolutely necessary. But, if it were my boat, I’d have one installed.

[n2ratfishin]

I don't have the WP sensor hooked up on my Merc 1000 SC Tach. You know that connector is at least another hundred, it's a boat LOL. I DO have the water temp hooked up. I don't have a JP.

[TritonTRXV8]

With the newer, more reliable engines, I personally do not have one, nor see the immediate need to get one. By gaining experience on the water, you will know it if you "overtrim" an outboard.

FYI, a water pressure gauge does NOT warn against overheating. It warns against a water pump impeller going bad that may LEAD to an overheat. Overheats are not always due to lack of pressure. Stuck thermostats, engine timing, lean carburetor are other reasons. Outboards typically have an overheat buzzer that warns of overheat. If overheat is what you are interested in then a TEMPERATURE gauge is what you are after. Typical racing boats have both gauges because they monitor two very different situations. If you are still stuck on a pressure gauge, some engines can have them plumbed into the tell-tale and will work fine. Others do not. The idea is to install a new impeller when you install the gauge. You then note the idle, mid-range, and wide open throttle pressure readings. If those number change significantly you know it is time to service the impeller again. I just replaced my impeller on my 2015 Yamaha 115 four stroke, and the one I took out, in terms of wear, looked just like the new one I put in.

Your mileage may vary, but for me personally, I choose to spend the $$ elsewhere. Others here may have a different opinion......

Water pressure gauge tells more than just the impeller condition. If you fish alot of grass and weedy lakes blocked water intakes can cause overheat which a water pressure gauge can warn you of. You dont want to rely completely on the engine gaurdian alarms often that is when its too late and motor goes into limp mode which isnt fun. I wouldnt own a boat eithout one. On a merc engine a mercmonitor is the way to go.
Con

[KP1923]

Water pressure gauge tells more than just the impeller condition. If you fish alot of grass and weedy lakes blocked water intakes can cause overheat which a water pressure gauge can warn you of. You dont want to rely completely on the engine gaurdian alarms often that is when its too late and motor goes into limp mode which isnt fun. I wouldnt own a boat eithout one. On a merc engine a mercmonitor is the way to go.
Con

All good points.....thanks.

Ken

[billnorman1]

I have first hand experience as to what a plastic bag wrapped around the motor leg will do. Without a water pressure gauge I junked a perfectly good 65 HP Evinrude back in the olden days.
My 4 stroke Suzuki doesn't have a dedicated water pressure gauge tap as far as I know but it does have some kind of sensor and an idiot light.

[jtracc]

The water pressure gauge that my ranger has from the factory is not very accurate and very tough to read at lower speeds. Your best bet is to get a digital merc monitor. I also have this, very accurate and real time info. Plus you get tons of useful info. I wouldn't spend the money on a gauge but I would spend it on a merc monitor.

[slonezp]

Should be a trim stop at WOT if you're set up right. If you're not running balls out, you can overtrim.

[Panama]

No, it’s not absolutely necessary. But, if it were my boat, I’d have one installed.

Everybody has different opinions on lots of things... Mine is same as the above. My RT and Yamaha did not come with a water pressure gauge and I did install one. I feel better with it. These engines and repairs are so darn expensive now and everybody runs trim and also fishes shallow so much. I fish around a lot of grass and weeds in Florida and I just feel better looking down and seeing that there is water pressure and looking at the pee stream out of the motor is not a good indicator. I added one because I think it is worth having in my situation and again.......it's cheap compared to any type of repairs. Real cheap.

The monitor would be better by far but the water pressure gauge is good if you don't want the monitor.

[Casslaw]

I agree with Panama. I can’t see the pee stream out of my Etec 90 but anything over idle and my gauge goes between 20 & 30 right between the little arrows that show you the “good” range.

I can either break my neck looking for the stream or look at my dash. I’ll be glad I have it when I add the jackplate.

[slonezp]

Water pressure gauge tells more than just the impeller condition. If you fish alot of grass and weedy lakes blocked water intakes can cause overheat which a water pressure gauge can warn you of. You dont want to rely completely on the engine gaurdian alarms often that is when its too late and motor goes into limp mode which isnt fun. I wouldnt own a boat eithout one. On a merc engine a mercmonitor is the way to go.
Con

Regarding the Guardian alarm. I can tell you from experience that, on my ProXS, at WOT it is barely audible. Let me preface this by saying, Just because the peehole isn't peeing, doesn't mean the water pump isn't operational. The peehole hole can get clogged and have no effect on the water pump. I had one occasion where I was flying across a lake and thinking to myself "What's that noise?" while the alarm was going off. Once i realized what it was, I dropped to idle and pulled the cowl off. Fished a few hours and then idled back to the ramp. Got home, backflushed the motor and all was good. That being said, I am positive i was clogged with dried algae from the week before, not something I picked up that day. Had I backflushed the motor the week prior, it never would have happened. I have backflushed after every outing since then.

Those of you with a water pressure gauge. Are you watching it? I don't pay any "regular" attention to my gauges when I'm running. In fact, on my last trip before winterizing, I noticed my fuel gauge is not illuminated. I have no idea if it just started or if it's been like that for 6 years.

[RyanJ]

Water pressure, trim and tach. 3 gauges one needs IMO.

[Team Colibri]

Nice to have, not a must have. I have never had one in my 25+ years of boating and I don`t have one for my (2018) 115 Pro XS now either.

That said, I would strongly recommend using one of the Merc gateways as long as your engine is compatible. I have both VW Link an VW Mobile, which is overkill by several miles, but having one of them is great. VW Mobile is both as budget friendly as anything will get in the world of boating, and gives you more info from your engine than you will ever need. Including alarms, hours since last service and engine-status in general.

[Casslaw]

The only 2 gauges I watch like a hawk are my trim gauge and water pressure. My motor is mounted too low so if I trim too far up I will porpoise so I know where the sweet spot is on my gauge. I also watch the water pressure gauge because...I’m in Florida and we have all kinds of weeds the FWC hasn’t killed yet!

Id know by the sound of the motor if my tach needed watching, and I don’t to fast enough to need a speedo!

[TritonTRXV8]

Regarding the Guardian alarm. I can tell you from experience that, on my ProXS, at WOT it is barely audible. Let me preface this by saying, Just because the peehole isn't peeing, doesn't mean the water pump isn't operational. The peehole hole can get clogged and have no effect on the water pump. I had one occasion where I was flying across a lake and thinking to myself "What's that noise?" while the alarm was going off. Once i realized what it was, I dropped to idle and pulled the cowl off. Fished a few hours and then idled back to the ramp. Got home, backflushed the motor and all was good. That being said, I am positive i was clogged with dried algae from the week before, not something I picked up that day. Had I backflushed the motor the week prior, it never would have happened. I have backflushed after every outing since then.

Those of you with a water pressure gauge. Are you watching it? I don't pay any "regular" attention to my gauges when I'm running. In fact, on my last trip before winterizing, I noticed my fuel gauge is not illuminated. I have no idea if it just started or if it's been like that for 6 years.

Wind noise cruising can make the alarm barely audible i will agree with that. I installed a red led indicator light for that reason its very bright and catches you eye. Im a regular gauge watcher same with my vehicles anything i drive honestly im weird like that so yes i would notice if something was a miss lol.