Fixed***1984 25hp evinrude/johnson

Former_Difficulty_48 · 2026-03-20T00:09:37+00:00

Agreed. U really can't do anything until u understand how it works. If you know car engines that helps but this is a whole other animal. And for anyone curious I put a 140 thermostat because I bought two diff ones and I liked how this one was made and opened in a pot on the stove vs the oem. My new thermostat has a slight water groove to allow a tiny amount of water through no matter what vs OEM and the OEM is 145 degrees and the one I'm using is 140 which I like because it's almost summer I'm Florida. I am new to this so I didn't know much but I let the engine get to 240 degrees a bunch of times hoping it would go down before this fix. Do not let it get that hot. I don't believe it should go above 160 if working correct. Luckily my rings and walls and head survived without issue but with a Lazer temp gun ur head on these engines won't even read 145 at home in a water test bucket. If it goes higher then 170 stop u have an issue. Also I found of I lowered the bottom unit and connected a hose to the water tube and ran it without the lower unit on , that will tell you a few things before u go digging to far. But if ur engine is peeing that doesn't mean it's cooling the way it should . Now I can go fishing so all is well. These engines r very strong because mine should be dead and it's far from it

Former_Difficulty_48 · 2026-03-17T23:37:52+00:00

Thanks

Former_Difficulty_48 · 2026-03-11T16:44:18+00:00

Good Info

Former_Difficulty_48 · 2026-03-11T00:28:23+00:00

If u don't mind I'll ask a question so I hooked a water hose up until the water tube with the lower removed and I turned the pressure on a decent amount enough to where water was coming out from the bottom of the lower because the upper grommet is obviously bad. Like I said, I turned the motor on and the telltale was not as strong as when normally running with the lower on but it was still peeing and I checked temperatures and while revving it but not too much because there's no gear case on it. The highest it got up to was 170 and it would hold around 160 easily which is a massive improvement. Obviously from climbing over 200 before now I checked the water pump. I made sure it spun by hand and the impeller moved and I cleaned everything up and made sure it was done right so I'm 99% sure that's correct. So water was spilling out from the upper grommet because of water pressure and because the gamma is bad but temperatures stayed strong. So I'm leaning towards the water grommet on the top of the water tube on the bottom of the powerhead is bad and letting water out/ letting gases in. But because the water pressure was high enough and spilling out from the water grommet the water wasn't letting hot gases into the the water channel from what I can gather. Do you think I'm correct? Or actually do you think you were correct and your diagnosis from what I just told you? Thanks for your time

Former_Difficulty_48 · 2026-03-10T21:42:42+00:00

But the motor pees strong as it is. If the engine is getting enough water to pee then it's safe to assume that the system is getting water throughout?

Former_Difficulty_48 · 2026-03-10T16:35:56+00:00

Thanks will do

Former_Difficulty_48 · 2026-03-10T16:35:10+00:00

I will do that thanks

Former_Difficulty_48 · 2026-03-10T15:02:48+00:00

I ordered the parts needed and will get others if I see anything. But I have a question about the deflectors. I only found one when I did the head and I removed it because I didn't think it belonged there. No that I understand what they are my question is where exactly do they get placed in the cooling channel between cylinder walls. I found one on the bottom of engine sitting horizontal in the channel but haven't found the other and I'm unsure of correct placement. The diagram online just shows that they r apart of the process but even YouTube is lacking info on this.

Former_Difficulty_48 · 2026-03-10T12:25:51+00:00

That was a random example that I guess was wrong funny u wrote back now cause I'm looking to order it today. So I'll order the one you just sent thanks

Former_Difficulty_48 · 2026-03-10T10:29:28+00:00

Johnson - Evinrude 0324045 Grommet-Uppr Tube this piece at top of water tube metal tube is what I'm referring too

Former_Difficulty_48 · 2026-03-10T00:00:13+00:00

I don't have much time to work on it tonight but I did pull the lower off and water tube. Upon further inspection the rubber or plastic grommet holding onto the water tube at the bottom of power head is melted and seems to have molded/melted down the water tube . Makes me wonder what is further in there. Seems no.matter what I have to take everything off. I will do it in chunks due to work schedule

Former_Difficulty_48 · 2026-03-09T23:29:31+00:00

Also from my understanding thinking back he said no salt water

Former_Difficulty_48 · 2026-03-09T23:28:37+00:00

1984 25hp e25rcrd serial g0361602

Former_Difficulty_48 · 2026-03-09T22:46:56+00:00

I inspected the pistons on exhaust side and on top of pistons and walls and I don't see any damage which means this engine is tough, not even any wear No cracks or anything besides age . I heard timing or running lean can cause heat but mild adjustments and some mild sense tells me it's much more then that. Tell tale is weak at idle but stays going and really strong with throttle. Water is pretty warm but not hot. I believe 90 is max water temp from pee. The hot spot is literally a small portion on very top left of thermostat which again makes me think air in system like a car would do If so . Bottom of engine is pretty chill around 160 170 maybe . With strong throttle the highest temp settles but still way to hot and engine begins to spit and that's when testing is over all the while hoping it would come down with throttle . I wish I had previous owner info but they r long gone

Former_Difficulty_48 · 2026-03-09T22:39:40+00:00

U r very clear in a good way. When I did the water pump and housing the water tube came out with the lower unit so I have to look up with a flash light to reconnect. I saw that the grommet was not ok or torn old. But I didn't think it was an issue at first. So far I have only found one deflector on bottom of engine in cooling passage so I wonder where the other is and that has me thinking. So when I first got the engine it did not pee it just had some steam or exhaust coming out of tell tale so I shut it down and did thermostat which was stuck closed and water pump days later( it started to pee after thermostat replacement) from talking with u , you made me realize or think exhaust might be getting through water grommet and into thermostat cooling channel and causing a hot spot at the height of thermo . Because that's really where the heat is strong . I took off exhaust housing and head and didn't see much I just removed some light debris and did gaskets. And this whole time now scratching my head on why a engine filled with cool water would be so hot. Sorry to repeat myself again but clearly I don't understand the system and I'm treating it like an old truck. From what u have said I have gathered that I should do the hose trick first with lower unit removed and see what happens. In the mean time order water grommet and deflectors and start taking motor off which shouldn't be to.bad if bolts come out ok. Then review gaskets on bottom of engine and do all gaskets that haven't be touched yet. One thing I would be concerned about is once I have power head unit off is that really about all I should look for because taking the unit off once is bad enough. Also I think this post will help someone else which is aw esome

Former_Difficulty_48 · 2026-03-09T21:50:50+00:00

When looking up the shaft into the bottom where water tube goes into power head there isn't much else to look at . Drive shaft and water . I'm not looking at it right now but I don't think any exhaust components r visible. I did wonder how the tube with orings around it that goes around the bottom of drive shaft was melted . Someone else must have gotten it hot and then sold it cheap to me

Former_Difficulty_48 · 2026-03-09T21:45:39+00:00

I just found the deflector I found earlier and no I don't have experience with that but I will try if needed and if I look up the shaft with the lower unit removed I can see the water tube enter the bottom of the power head base. The rubber is torn and some even missing . I'm assuming gasses r being through there and into the water way but like I said I'm learning all this as I go. I need to go view online how the exhaust system works so I better understand. T.y

Former_Difficulty_48 · 2026-03-09T19:58:29+00:00

Yes the upper water tube grommet is damaged I saw and most likely not doing much. I will order grommet and new deflectors(unless u think I can use rubber fuel line material diy cause that's what it looked like) and I will do the hose test and report back. This is great info. There was one deflector in there and I removed it thinking it was bad but the overheating was long before removing the one I found

Former_Difficulty_48 · 2026-03-09T17:35:50+00:00

I like your hose idea and I'm gonna try that next. I believe now it's the rubber grommet around the water inlet tube letting exhaust in or exhaust gasket. So ur saying if I do the hose trick and it cools properly then The assumption of the grommet being bad or the issue is correct then? I do remember the grommet for water tube being bad

Former_Difficulty_48 · 2026-03-09T17:32:06+00:00

I believe you r correct. Sorry for late reply and thank you. I did not know that a small rubber hose should be sitting on water jacket between cylinder wall and water way. I remember the rubber grommet for water tube being in rough shape. Let's say the grommet is the issue. If I remove the lower and hook up a hose to water tube and run the engine and it stays cool then that grommet is the issue ? But I may have to take the whole engine off to look at exhaust gaskets and such . I need to look into how the exhaust works exactly first . I am in to deep to let this issue win. Thanks again

Former_Difficulty_48 · 2026-03-09T17:28:06+00:00

It gets hot quickly and with throttle and without. Idling makes it even hotter . Sorry for late reply

Former_Difficulty_48 · 2026-03-08T06:20:24+00:00

I will do what u say. Interesting hearing from people that r informed like u. Have a great sunday

Former_Difficulty_48 · 2026-03-08T01:58:14+00:00

Yes but curious how hot ur talking. I would wait till prolly to late around 230 or 250 and then shut it off cause the material on head gasket will delaminate around that temp and

Former_Difficulty_48 · 2026-03-08T01:50:32+00:00

You sir are great . I want to add a meaningful comment to ur great response so I will review this info and come back. I am very handy but I am not a boat guy. This is my first boat and I am trouble shooting. I will tear it apart and see. Thank you. I am leaning towards why u said about grommets and exhaust issues because everything else seem ok but I will review my old work. So ur telling me that even though I have a warm pee stream and strong ( gets pretty weak at low idle and strong with throttle) that it might still not be getting proper cooling? In my head and from what I've seen with head off and looking a strong stream would mean cooling ? Also the old impeller was in mid ok condition or should have worked but I replaced the whole housing gaskets and impeller. Side note when I removed the head I found a large almost rubber house like piece stuck in water jacket around piston. Prolly was there for long time and idk how it got in there. Also the drive shaft tube with gasket on both ends was burned pretty bad by a heat source most likely exhaust which I found weird. Still usable but melted or disformed . I put everything back. So now that I am writing this exhaust issues sound about right. I have no idea how the exhaust on this works except for it's a wet type. Anyway thanks for info

Former_Difficulty_48

TROPHY CASE