Crossflow no water out relief holes at plane speed?? really need advice.

[rothfm]

Can can anyone tell me the path of those relief holes? I understand the impeller path and have the OEM diagram. What happens with
the relief holes/path/poppets? Really looking for input, as i've been working this cooling issue awhile.

1993 Johnson 115 bubbleback.

My issue at the moment is no flow at all out relief holes, on plane and warmed up. At Idle, i get a slight mist and light exhaust warmed up. Initially, this new to me motor had no stats, and bad diverters. Replace everything and It looked good on hose, albiet one side was a bit warmer than its 140 port side. Thought I was good to go!!!!

First in water test...Overheated at the ramp while I was tied up and monitoring with IR gun. Went from cold to 190-Both sides(new pump kit and great pee). I let it cool to 120, restarted and temps held at idle at 140-155 +- So we went out, and temps remained in spec. HOWEVER, ABSOLUTELY NO FLOW OUT RELIEF HOLES AT SPEED. I dont understand. Stats appear to be working. Is the path for this Onrush of additional "speed-water", the same as the pump flow basically? On muffs I have good even flow out the head hoses. And on muffs all exhaust and water seems to exit where it should.

I'm wondering if my initial overheat at the ramp was a vapor lock, as it cleared upon restart and never came back. Incidently, I have a couple of powerhead exhaust leaks making oily streaks down the leg. I thought it was minor, but could that be part of this problem?

Arggggg.....thoughts please

 

[emdsapmgr]

Re: Crossflow no water out relief holes at plane speed?? really need advice.

You've done a nice job of analyzing your problem. You are observant. A slight mist at idle is normal-indicates the thermostats have opened. Usually, when on plane you will get somewhat more flow from those two exhaust relief ports. Your idle temps of 140-145 are as expected, so sounds like your cooling system is functioning normally. 190 is close to overheating (the hot horn goes off at 212 degrees.) Not uncommon for those older engines to leak exhaust due to a bad powerhead base gasket. The gasket is cheap, but you'll spend about 3 hours removing the powerhead, cleaning up the gasketed surface, install the new base gasket, then re-installing the powerhead. The real reason to replace that gasket is that any exhaust leaking inside the cowling will get recirculated into the carbs while running. Not good. In addition to the exhaust leak, that gasket also serves to connect the midsection cooling water to the underside of the powerhead. Usually the defective base gasket still permits enough cooling water to get to the powerhead, but it is possible that some of the cooling water is leaking off and may not be getting passed up to the powerhead. Probably a good idea to replace that base gasket sooner rather than later, then recheck everything.

 

[rothfm]

Re: Crossflow no water out relief holes at plane speed?? really need advice.

Thanks EMD.. Was hoping you'd chime in

I know these motors pretty well. Have another all apart on a bench. Saving up for pistons. Was just surprised at the initial overheat..I know there are air bleed holes I was carefull with on the stats, so maybe it was just a air lock thing. Was also surprised at WOT no water out those holes.

So, we came home and opened up the stat housing again. (and cuz the bubble back is such a pain-I put another new set of everything in). All was/is good in there for sure. Was maybe thinking that at speed, water is not bieng forced fast/fast enough through to open the poppet plastic valves?? But I would think I'd overheat at speed of that was the case correct...Unless my PH gasket leak is more an issue than I realize and that fast water is not getting to where it should. Thats why I was asking if the path of that "fast" water is the same as Impeller water path.

 

[emdsapmgr]

Re: Crossflow no water out relief holes at plane speed?? really need advice.

One other thing which is overlooked inside the thermostat housing. The valve body. Looks like a pc of hard plastic, about 3/8" thick. There are two pinholes on that valve body. One for each stat. Their function is to let hot water bleed to the back of the housing where the stats are. That hot water will cause them to open. If those holes are restricted by sand, dirt, etc, hot water can't get around the valve body to open the stats and you can get an overheat on one or both sides of the powerhead. Hopefully you have not put it back together yet-I know what a PITA they are to work on..... Since yours is a later model, I believe your valve body has a larger, oval hole which will span both thermostats. Usually these don't cause the problems the older ones did..Their opening is much larger.

 

[rothfm]

Re: Crossflow no water out relief holes at plane speed?? really need advice.

Many thanks EMD....Yep, aware of the holes. It sprang apart so quick I didnt notice my prior orientation. but the when I did the second BRP set, I made sure it was in the correct way for sure--referenced pics on here as well.

UPDATE: I no longer have higher starboard temps on muffs (saw 149-161) at times. 2nd set of stats hits 144 both sides and stays there solid. I like it!!!

Flushed and back flushed also. But still dont have much water out the reliefs, even when upping the rpm's on muffs. I had zero during my water-test run yesterday before these new stats. Just a slight spit at idle..then nothing while underway. Unsure why. Where do these ports actually go? I blew in them, and flushed them. No apparand issue wile underway however-just no relief water. We'll see what happens in water with these 2nd set of stats now.

I also gotta look at props, tops out at 5k on tach..Believe I should be 5500+. And it doesnt sound like I'm reaching top rpm. I got several props, which way should I go to try to get it up in the higher area?

Thanks again.

 

[rothfm]

Re: Crossflow no water out relief holes at plane speed?? really need advice.

Many thanks EMD....Yep, aware of the holes. It sprang apart so quick I didnt notice my prior orientation. but the when I did the second BRP set, I made sure it was in the correct way for sure--referenced pics on here as well.

UPDATE: I no longer have higher starboard temps on muffs (saw 149-161) at times. 2nd set of stats hits 144 both sides and stays there solid. I like it!!!

Flushed and back flushed also. But still dont have much water out the reliefs, even when upping the rpm's on muffs. I had zero during my water-test run yesterday before these new stats. Just a slight spit at idle..then nothing while underway. Unsure why. Where do these ports actually go? I blew in them, and flushed them. No apparand issue wile underway however-just no relief water. We'll see what happens in water with these 2nd set of stats now.

I also gotta look at props, tops out at 5k on tach..Believe I should be 5500+. And it doesnt sound like I'm reaching top rpm. I got several props, which way should I go to try to get it up in the higher area?

Thanks again.

 

[emdsapmgr]

Re: Crossflow no water out relief holes at plane speed?? really need advice.

Sounds like your temp situation is on the right track. 144 is good! Visually check the water flow out of the exhaust relief ports next time you get the boat up on plane. You will want to go down a pitch on the prop. Say from a 19 pitch to a 17. Each prop size lower should bring your rpm's up about 300.

 

[rothfm]

Re: Crossflow no water out relief holes at plane speed?? really need advice.

Thanks again EMD...Water test later in the week to look at the reliefs on plane. I have to look but I do believe its a 19 pitch on there, and have a 17 to try. I did see a Joe Reves tip here about a way to check full advance at WOT with plugs out, and cranking. Might take a look at that to be sure.

FIXED: Exhaust streaks down the leg.....Found 2 (front) of the 6 PH bolts loose. After securing, and an long hose test--No more oily runs down the leg so far! Sweet.

Will update after the next water test, for anyone else interested.

 

[Fed]

Re: Crossflow no water out relief holes at plane speed?? really need advice.

Could you have been unlucky enough to pick up a plastic bag at the ramp?
Being 190 on both sides would sort of eliminate everything after where the water enters the outer cylinder walls.

(I also have a cooling diagnostic problem which I'll save for another thread but would appreciate it if you'd report back with your findings)

 

[emdsapmgr]

Re: Crossflow no water out relief holes at plane speed?? really need advice.

It's prefereable to re-torque those long powerhead bolts after the engine goes through a couple of heat/cool cycles after overhaul. Most of us do the head bolts, but..... Removing the lower engine covers is a sort of a chore, so many don't get retorqued. Good catch-hopefully that will resolve the leak. If you ever get into a 17 stainless prop, they have better bite than the alum....you can work on your engine setup. Maybe raise the engine a hole on the transom. You'll pickup rpm's. Less engine in the water=less drag=more top end.

 

[rothfm]

Re: Crossflow no water out relief holes at plane speed?? really need advice.

Goog thoughts..Will look into that drag and where the cav plate hits the water Its a 25". I do seem to have quite a bit of spray back there from the leg, Then again there is the speedo, transducer causing a bit of spray also. Will look.

The plastic bag...Maybe? I did go high on the muff's once also-both sides. Then one side always ran a little hot while the other was ok. The new 2nd set of OEM stats did fix that. I'm thinking I was getting air lock because both times from cold, both sides immediatetly climbed to overtemp without stopping, once on the mufffs and once on at ramp on my first test.

After doing them again, and playing close attention to the housing mid-plate and the little holes, and how they line up....that problem hasnt happened, at least on the hose anyway. Temps now both hold between 143-146 or so. Real nice

Will try to get in the water next few days and report back.

 

[Chris's CVX16]

Re: Crossflow no water out relief holes at plane speed?? really need advice.

FWIW I had similar issues a couple of weeks ago. Overheat alarm went off while I was running her on the hose. I looked for every hot piece on the motor and found that the hoses that went from the heads to the mixing block (under your bubble) weren't full of water. Well the port side one wasn't. I had no flow even at 3000 to the exhaust relief's. I ended up taking off the hose and looked for a blockage. I ended up using water and 50 PSI air bursts to dislodge what ever was causing my blockage (likely dried up sand). About 30 minutes later all buttoned back up and I get plenty of flow out the relief's above 3000. I decided that since I haven't looked at my water pump I would inspect and replace. It didn't look bad at all. Still a lot of meat on it but since I had one I replaced it. I now have water drizzling out the reliefs at idle in the lake and a bit more than a spray at idle on the muffs. Heads, cylinders and exhaust are all cool even after running.

When you changed your pump did you have the to use the rubber bushing to neck down from the output on the pump to the copper water line? I did though the previous pump did not and I think I have a lot more flow and a lot less bypass water in my mid section.

I too have a tiny bit of "ooze" down my mid section. I'll try looking into loose PH bolts. Sure a lot easier than taking the PH off to swap in a new gasket.

 

[rothfm]

Re: Crossflow no water out relief holes at plane speed?? really need advice.

Yep, impeller o-rings all in place as well as the water tube grommets..done alot of pumps. But i did go back in to a look at it.

During this problem, I've always had water pouring out the head hoses--nice flow. I believe I might have had that housing mid-plate with the two little holes reversed so the two holes were facing foward, and the one facing backward. Not sure, But putting in new OEM stats, and re-doing everything...Nice temps for sure.

My RPM issue may be link/sync related. My test run ran smooth but felt like it didnt get WOT at only 5k rpm. I was looking at the cav plate and it is just about at the bottom of the boat. I might come up a hole like EMDsmapper said. But I noticed when my throttle lever is all the way down, the carbs are not fully open, nor is the base timer up against its stop. In fact is is a full inch from the stop. This must be my WOT issue I believe. But I'm going to change props as well.

Going to look up the linc/sync procedure now..Belive it was a Joe Reeves posting. That will be next.

 

[emdsapmgr]

Re: Crossflow no water out relief holes at plane speed?? really need advice.

Not unusual for the sync and link to get off. When it does, sometimes the carbs do not open fully, but usually the spark advances fully. (The spark goes to full advance before the carbs fully open.) The fact that the engine is not able to function normally as setup should give you much hope. There should be more performance left in that powerhead-once adjusted correctly.

 

[rothfm]

Re: Crossflow no water out relief holes at plane speed?? really need advice.

Thanks EMD...Yep, gonna read up on the procedure tonight and give it a whirl. Between fixing that, a different prop and maybe raising it up one hole.....Should run pretty well. There may be fishing in my future yet!!

Will post result for others after I do the procedure and in water test again. Still very curious about what will happen with the relief flow during water test again.

 

[rothfm]

Re: Crossflow no water out relief holes at plane speed?? really need advice.

UPDATE:

EMD-Hope your still watching this thread......Had another overheat on the hose!!!!! Rggggggg....

Was going through the link/sync procedure today. Before and after I had it running for 10-15 mins at a clip and I always monitor temps. They were aok as expected (i went thru and fixed any cooling issues fully already). Link/Sync came out good and after going thru it, it really made sense. The motor was off and the carbs were not opening fully.

Anyhow.....After I was done. I restarted again, and motor shot from 70 to 190. I shut down. Let it cool to 110, restarted and it went to 143, opened stats and ran aok20 mins NO ISSUES AGAIN. This happened the other day at the ramp, and another day on the hose. It will then restart and run with fine temps.

I NOW REALLY BELIEVE THIS IS SOMEHOW RELATED TO AIR LOCK. EMD was mentioning those little housing mid-plate holes. I have the style that has the little two vs one larger one. Ive been into this housing several times (bubble back) and am absolutely sure it is installed correctly and the holes are clear. I "Re-replaced" everything in the stat housing just in case I got a bum set.

this has happened a couple times now(high on both heads)...and after restart--comes to temp, stats open and all is well. Do some people open those holes up to a larger size or change the mid plate adapter to the version that has one larger hole?

Hoping someone has had this happen and their resolution, of someone that might have additional insight. In the meantime, i'm about done getting back into that area. At least I believe I know what it is, and can watch for it. Its soon time to go fishing.

 

[emdsapmgr]

Re: Crossflow no water out relief holes at plane speed?? really need advice.

You're tuned in to the different aspect of the cooling system. Basically two scernarios on that engine. 1. Dead idle, or just slight throttle. The impeller provides the only cooling water to the block. The thermostats must open to flow cooling water out of the block. They must open at 143, and the idle temps should maintain around 143-155. Pressure relief valves closed 2. When on plane up to WOT. Forward movement propels large amouts of pressurized cooling water through the system. The extra volume/pressure causes the nylon pressure relief valves to open in the thermostat housing, flooding the powerhead (both heads) with extra cooling water. This extra cooling water will actually cause the powerhead temps to decrease, up to maybe 20 degrees. (maybe more in really cold water.) This is normal. You may get these pressure relief valves to open on the garden hose if you rev the engine slightly. I'd be interested if you can see the opening of the pressure relief valves as a result of a change/decrease in head temps.

 

[Fed]

Re: Crossflow no water out relief holes at plane speed?? really need advice.

I wouldn't be surprised if there was a bit of lag when the thermostats first open because there is only a small flow through the pin holes, after opening I'd expect they would become far more responsive.

I notice in my manual for testing with melt sticks it says to first run the motor at 3000rpm for at least 5 minutes before applying the melt sticks. I ask myself why not use the melt sticks before even starting the motor then let it come up to temp from cold?

The answer I come up with is, typical manual... we tell you what to do but not why.
Do they know these temps will initially run up high and screw up the melt stick readings therefor advising to heat it up & stabilize first?

I remember having a very responsive temp gauge in a car and it did exactly as your motor, initially up high then down and carry on stable.

As a point of interest I have been told by a very knowledgeable OMC tech that at higher rpm the thermostats will actually start closing due to the increased water flow and that these v4s can flow enough water to cool a 4 Litre v8.

I wouldn't completely trust an IR gun for outright temps, they are very dependent on emissivity, great for comparisons though.

More random thoughts, I'm thinking as I'm typing...
I'm convinced my thermostats never open on the flusher due to high water pressure & me cranking the tap wide open, I think I'm over powering the poppet valves.
How do you flush, enthusiastically or not?

 

[rothfm]

Re: Crossflow no water out relief holes at plane speed?? really need advice.

Hmmm, Thanks both....appreciated. The motor does run nicely, idles great and seems to be in sync good now.

EMD, I've only done 1 "in water" test...At speed/on plane and no flow out reliefs. On the muffs when warm just a slight spit(very slight). On plane, I measured while running WOT and temps were as you described. they cooled down to 90-100 or so as if a "large" amount of water was flowing----but it sure wasnt coming out the reliefs! This was before i did a 2nd set of stats. Havent been back on the water since.

Not sure if this observation is related to this random overtemp issue or not? On the muffs, If I up the RPM's I still see no relief flow(almost nothing really).

So thats the symptoms 1) random overtemp/both sides, then fine at restart 2) no flow at plane speed at relief ports (just a spit at idle)

Side note: I've removed hoses and have great even flow bot sides, completely new thermostat components etc..I've backwashed and confident i have no blockages. When I restart, it will climb and remain at 140-150 nicely.

Is there something just behind the relief holes that can clog..what is the passage to/from. Maybe I'm getting the "large" amount of water at Plane but just not coming out the holes?

Yea, i thought maybe the stats were just slow to fully open due to possible air lock at those little bleed holes in the stat housing mid-plate, Once restarted, it will be fine. But this relief port flow sympton, has me guessing at everything again.

 

[Fed]

Re: Crossflow no water out relief holes at plane speed?? really need advice.

On the muffs when warm just a slight spit(very slight).

Mine's exactly the same.
I have seen utube videos of water gushing out of the relief holes but I don't think that's normal, probably some creature built a nest in their exhaust pipe. I've never checked mine at speed.