HELP!!! 175 pro xs overheat

[Joe Genovese]

I have a 2015 175 pro xs....serial #2B112622. Last fall I started getting warning beeps that would not let me run wide open. Took it to Bass pro so they could hook it up and read the codes. Overheating. Said both thermostats we're stuck open. Replaced both thermostats and bought vessel Vue. Went to lake and still overheating. Vessel Vue was showing unrealistic temperature. If it was that hot it would seize. Is there a sensor that sends the temp? Could it be my problem? Got good pea stream, but just put new impeller in....old one seemed ok, but covering my bases. Any suggestions???

[Joe Genovese]

Also, vessel Vue said starboard side.

[Riccochet]

What pressures are you seeing? Idle and as RPM's rise? What is the "unrealistic temp"?

If you run it on muffs in your driveway, at idle only, do temps continue to rise past 150? If so you may want to check the poppet valve. Could be stuck open.

[SilverFox579]

Did you get printouts when they read codes? If yes, post pics here so the pros can help with diagnosis.

Normally, thermostats stuck open will not allow engine to come up to operating temperature not overheat. Stuck closed, definitely possible.

It is not recommended to do an "impeller only" on any Optimax. The 2.5L Optimax requires, at minimum, an impeller, plate, and all 3 gaskets (one either side of the plate and one below the pump base). If the pump cover is in good shape it can be reused. This service should be performed annually (every 365 days) or 100hrs whichever comes first.

What were the unrealistic temperature values displayed by VV?

It's possible you may be experiencing a compressor overheat, I would remove, check, and clean the compressor strainer as appropriate. To do so you'll need to remove the cowl and port side lower.

Dave snuck one in while I was typing and he mentioned something I was going to edit and add to my post - stuck poppet.

[Joe Genovese]

Ok guys. I did the entire kit....housing, gaskets and all. Sorry bout that. I didn't get a print out. VV showed temps rising to around 300 really quick after alarm went off. Pressure at idle I want to say was around 8 and never gets over 20....been that way from day one. None of this was done with muffs, always on lake. Thanks a bunch guys.

[Riccochet]

8 psi seems kind of high...at least to me.

Might have some kind of obstruction in the cooling loop somewhere.

[jbh3]

There's more than one "overheating" code. As Silverfox stated, I would look at cleaning the compressor strainer ASAP and proceed from there.

[Joe Genovese]

Thanks guys, gonna tear into my manual when I get home. Linda new to this stuff. Worked on dirt bikes forever, but when I took the cowling off this thing I just stared for 20 minutes.....Holly crap there's a lot of stuff on this thing.

[potomacbassin]

Definitely clean the compressor strainer. If you’ve never cleaned it I guarantee it’s filled with crap. I clean mine twice a year

[Joe Genovese]

My nitro's about 3 1/2 yes old. Got 60 hours on it, and 90 percent of the hours are no wake hours cause I live in Illinois. I've never cleaned that screen. So I'm sure it's a mess. Thanks again guys!

[potomacbassin]

Here's a good thread on it. http://www.bbcboards.net/showthread.php?t=565408

One of these pictures is actually my strainer.

[Riccochet]

Here's a good thread on it. http://www.bbcboards.net/showthread.php?t=565408

One of these pictures is actually my strainer.

Good write up. Just note that there is no rubber access plug "C" on the 175 to access to the rear lower cowl bolt. You'll need a 8-10" long 1/4 drive extension with a 1/4" knuckle and 8mm socket on the end. It's tricky to get to. Use an extension magnet to remove and reinstall the bolt. Unless you have really small hands. I also use the knuckle to remove the upper front bolt as it can be hard to get to with the rigging coming through. Also, there is no need to completely remove the port side lower cowl, just pull it out of the way enough to access the strainer. Otherwise, there are two phillips head screws on the rigging collar that need to be removed so the rigging can be pulled up enough to get the port side lower cowl out. Not necessary for this task though. Things are a bit easier on the 3.0 motors.

[potomacbassin]

Good write up. Just note that there is no rubber access plug "C" on the 175 to access to the rear lower cowl bolt. You'll need a 8-10" long 1/4 drive extension with a 1/4" knuckle and 8mm socket on the end. It's tricky to get to. Use an extension magnet to remove and reinstall the bolt. Unless you have really small hands. I also use the knuckle to remove the upper front bolt as it can be hard to get to with the rigging coming through. Also, there is no need to completely remove the port side lower cowl, just pull it out of the way enough to access the strainer. Otherwise, there are two phillips head screws on the rigging collar that need to be removed so the rigging can be pulled up enough to get the port side lower cowl out. Not necessary for this task though. Things are a bit easier on the 3.0 motors.

Good point on the hard to reach screws. What I use is a pickup tool to hold onto the screw while I line up the screw to put it back together then push it in the whole with the socket.... I've found this to be the easiest method.

[Joe Genovese]

Ok, took the screen out and absolutely nothing on it. Put everything back together, and in the driveway I hooked hose to back of motor and back flushed it for a few minutes. Then I put muffs on and started it. Turned vessel Vue on and watched water temp and pressure. BTW, I was wrong on earlier pressure readings...it's 4 at idle at 580 rpms and dropped to about 2 when thermostats opened. Thermostats appeared to open around 175 degrees and within a couple minutes it hit 208 and alarm went off. Vessel Vue instantly chimed a warning of overheat on starboard side again. So, I'm trying to figure out where the poppet valve is on this thing. Google isn't helping. Anybody know? I've never messed with or seen one.

[buster502]

go under dons website (parts)and put your serial number in,and look for poppet valve it might have location and part numbers,if it is like the older efi motors you can fallow one of the water hoses from the thermostat down to the poppet valve,do not use after market parts and dont change the rubber that mounted inside the motor if it set up like a efi motor

[Riccochet]

You'll need to remove the lower cowl on the port side. Once that is removed unbolt the 3 or 4 relays that are there, unbolt the starter relay, unbolt the plate they were mounted to, but don't remove the wire looms that are attached to it. This allows you to swing the whole mounting plate toward the bow. Use a bungee to hold it there. Now, behind that plate is your poppet valve cover. It will have a hose going in to the stern side of it. There are 4x 13mm or 1/2" bolts holding it on. It should look like this:



Just a heads up, the gaskets are cork and you're more than likely going to rip one when you remove the cover and middle plate. So you'll need to replace both gaskets.

Be about $30 in parts to rebuild it. Everything you'll need to rebuild it are listed below. I ordered from crowleymarine.com. Just go on there and search for your engine model number, then look in the "Exhaust Manifold and Exhaust Plate" section.

2x gaskets
1x washer
1x deflector
1x diaphragm
1x poppet
1x spring
1x grommet
1x grommet carrier

You may not need the grommet carrier, but it's cheap and if yours is cracked it's better to replace it.

[Joe Genovese]

Got the cover off, but when I try to pull the big round thing (assuming that's the valve) it's like I'm pulling on a spring and it doesn't move but 1/4 inch.....does it require some force?

[buster502]

there is a special way that it goes back together,something about the screw and getting in align right and tight ,you might want to ask don or joe or ??

[Joe Genovese]

ok, it was definitely sticking, but it came out. Slid it in and out and it seems free now. Put it all back together and it's still overheating. I'm going to order a new one monday anyway, I suppose it could be screwed up and is sticking again. I am a little concerned with my thermostats...They seem to open around 180 degrees, but all I've read the last few days has everyone running much cooler than me. What temp should my thermostats open? And what temp should my motor usually maintain? Thanks for any input guys!

[buster502]

do you have a mercury service manual for that motor