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

[rothfm]

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

Thanks Fred,

I flush "enthustically" as you asked...Got me thinking maybe I am overpowering the poppets (but still dont see flow) and the hose water is cold enough were I'm coincedently hovering 140-150. Hmmm, but that would be too lucky to be at the stat temp just by chance.

When the stats do open, I see flow start at the slotted ports just above the cavitation plate--so I'm sure they do open. I've even popped off the head hoses to see good even flow.

On plane, Like EMD stated---Temps actually come down. SO I'm led to believe I get this "in rush" volume of water. I guess I wont be concerned for now what comes out the relief ports.

But the intermittant, random shoot up to 190-to-overheat alarm....has me stimied. Happened 3 times. 2 on muffs, once at the ramp in the water. Almost like air lock or something...each time, let sit a bit, restart and fine.

Has anyone opened up those little housing holes before, or joined them together into a larger hole to bleed into the stats?

 

[Fed]

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

Does your overheat alarm actually go off?

 

[rothfm]

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

got alarm once at the ramp, and the other 2 times on the hose would have buzzed alarm, if I didnt shut down(saw 190). Again, most times its fine either cold start or warm. But when it does this, I just let it cool to about 100, restart and it comes back up to temp and then stays at 140-150 aok. Very weird.

 

[rothfm]

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

Was just mentioned the relief port lack of flow, as an observation. Not sure if/how related or not.

I had this running several times nicely today on muffs. Spent time on my link/sync procedure. Ran it afterward (muffs) fine, then restarted 30 mins later after working on a car, and it got to Alarm point. Shut down, cool to 110 and restarted and idled for 20 mins-muffs.

Still thinking of providing more "bleed" thru those little holes than there currently is...if that is ok to do.

 

[Fed]

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

Did you do your water pump by the genuine OMC book with attention to the little air bleed groove?

To me setting off the alarm means you have a problem for sure.

With both sides getting hot equally I still think it has to be something common to both sides.
That should rule out deflectors, t'stats, bleed holes in t'stat housing, poppets etc.

For a while there I didn't think you had a problem but setting off the alarm is making this very interesting now, keep up the good work.

Edit: I wouldn't make the bleed holes any bigger the OMC guys knew what they were doing.

 

[rothfm]

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

Oh yea, OMC manual. All original BRP/OMC parts. Even when back in and replaced stats and related new again! Good flow no apparant blockages. I can run it unlimited on muffs and see 140-150. then shut down, restart awhile later--and it might go up toward overheat. I dont get it.

Will keep plugging away!

 

[emdsapmgr]

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

Nice water test with head temps. Sounds like the pressure relief valves are working normally. So, the overheat is really an idle/dead slow issue. Is the overheat always related to one side of the engine? Another test might help clarify the problem. Temporarily hook a 0-30 lb water pressure gauge up to the telltale hose barb on the back of the engine. Run the engine at idle. I'd be looking for 5-6 lbs of idle pressure. If you run it on the lake, maybe close to 20 lbs at WOT.

 

[rothfm]

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

Thanks EMD....When this happens it will be bothside hot and yes, just sitting on muffs or in water at idle. Good idea about the pressure guage. I will do that. Will be doing another water test saturday. New impeller components, and strong stream. Buy ya never know, maybe somethings going on down there where it looks like its still peeing but the pressure drops off...but at the time it sure seems strong.

I guess popping off the hoses when this happens would be good. I'm more concerned with shuttitng it down so it can cool. But If I can pop the hoses, quickly when i see it climbing up there---that would be good to see real-time what is coming out at that moment.

Thanks guys...Will report what I find after more testing.

 

[Fed]

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

I'd pop the hoses (heads to tstat housing) and run it on the muffs, wait for an overheat and check the flows.
After re-reading the thread a few times I'm not sure if you've already done this.

 

[rothfm]

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

I've done that a bunch of times checking flows, and back flushing etc....But in thinking back, not at overheat time. I'm more into shutting it down to get temps down asap. But If I can catch one of these times when temps keep climbing, I'd like to quickly pop the hoses off before it gets to buzzer temps--to see when I got coming out. I'm stymied.

 

[Fed]

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

Maybe you could get more definitive answers running it in a tub?
Take the tap water pressure & muff tightness completely out of the equation.

 

[rothfm]

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

Yea, I want to make a small tub as its quieter for the neighbors also...But this did happen at the ramp also, tied to the dock at idle.

 

[Fed]

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

Yep I fully understand, what I was getting at is running on the muffs might be masking the problem.

Just to confirm...

Did you do your water pump by the genuine OMC book with attention to the little air bleed groove?

You didn't directly answer this and I got the feeling you were responding about the bleed holes in the thermostat housing rather than the water pump.

 

[emdsapmgr]

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

Overheat issues can also be driven by restrictions in the cooling passages. If you continue your testing and nothing seems to add up, you may want to pull the head covers off both heads and check the cooling passages for any salt, sand, debris, etc. If the head covers show signs of restrictions, you may have the same thing going on in the powerhead itself. Then pull the heads and visually check for restrictions around the cylinders. Also, make sure the rubber water deflectors are in their proper postion.

 

[rothfm]

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

Hi Both,

Fed: Yep, did the Pump components by the OMC book and all original parts. Was familiar with the air bleed. I can drop the lower again to check however.

The first thing I did when I started this little project was pull the heads, and the deflectors were in awful shape. I changed them, and have even removed heads again to ensure they have remained in position. I've backflushed from the Head outlets back thru the block and out the leg and had good flow-both sides.

I havent removed the head covers as of yet. Something to look at. I will be doing some more testing today after work in the driveway, with a water test Saturday.

Will update. Thanks again.

 

[rothfm]

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

UPDATE: Problem fixed??? Time will tell.

Ok, to recap for others..new to me motor needed stats, deflectors, head gaskets etc...I did them and then had one side running hotter (up to 160's) then the other. In working this I had, at times, climbed to overheat both on Muffs, and once at the ramp in idle. but not all the time.

My first set of tstats, were on my bench and "fairly new" but not brand new--I used them without checking them. Was chasing my tail with one side hotter and the occasional overheat....After putting in brand new BRP stats, I got even temps finally. That was my PHASE #1.

BUT, on muffs I began to experience a intermittent overheat on BOTH Banks!!! (different symptom), also no flow out the reliefs. Apparant good flow out the hoses, strong Pee, DROVE me nuts!!!! Went back into the bubble back stat area and heads again to double check diverters, back flushed, Salt-Away, recheck lower unit--everything. Issue remained.

Today, I stopped by Wallyworld and got a small plastic garbage can that would fit the lower unit to run in. WHAT A DIFFERENCE. immediately I had more water "spitting" out the reliefs on cold start than before...and as soon as the stats opened, I could tell the difference again, more water out the reliefs. Then if I upped the RPM's more water yet. Measured everywhere, the temps were great.

Also...the temps drop from 144 to 110-115 as I would expect they would when more volume comes out the reliefs when the poppets open. I restarted a bunch of times from cool temps---and never, ever got above 145 anyplace. And coupled with the recent link/sync, running in a barrel, with the cowl on--Man does it sound good and smooth.

SO....my muffs were dumping so much water, not enough for proper cooling I guess. I feel stupid--but water normally goes everywhere on muffs, so I didnt pay much attention to it! I was going to do a fuel filter and some other things, but first went right to the barrel. Huge noticeable difference.

I'll post again if my Saturday In-water test proves me wrong. But I experienced a marked difference and feel my cooling system is now in good shape.

Thanks in advance to those who helped and got me thinking...I thought about this all day today, The wisdom, guidance and community here is second to none!

Mark

 

[rothfm]

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

UPDATE after anther water test.

Definitely bad muffs...All the cooling work was needed to be done for sure. But my muffs were not providing enough water. Since running/testing in a barrel, and Saturdays fishing trip----all is well, yeayyy. I'm so happy.

Had my IR gun on the trip, taking "samples" many many times...Cooling worked as it shoud. 145 at idle, with some spray out the reliefs idle. On plane, temps drop to 115 or so, with some water out the reliefs. Never got above 149 or so at any time.

Word to the wise, if your dumping tons of water from the muffs--it may not be enough "uptake" to the block, yet pee stream appears fine. And to those of you that like to REV the engine on muffs? DONT. I hate seeing those youtube vids of people winding out their motors on muffs, bad practice. Hose water provides marginal supply at best.

 

[emdsapmgr]

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

The old OMC designed impellers usually will suck water for any reason. It's some newer Merc that usually have problems on the muffs. Good catch. Guess you'll be getting a new set of muffs for Xmas!

 

[Fed]

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

The muffs don't account for the time it overheated in the water?

 

[rothfm]

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

EMD, new muffs for sure..I really like the barrel though!!! Can hear it purrrrr.


Fred: Yes, I wondered about the overheat at the ramp too....I did so much I had to think about what came 1st (should have made some notes). The ramp overheat was on the 1st set of Stats where one side would climb toward hot, before fully allowing water to pass. After the brand new OEM stats went in, no issues since. I ran it every way I could including extending trolling time. All has been good.

NOW, I got a slight Powerhead gasket leak streaking my nice white paint job...RRRRR! That will be a fall project at this point.

Thanks again all.

Mark