I think I need a low water pickup lower unit/ overheating wile running

[Donzi22zx]

I have been having a constant overheating problem with my 22ZX, I have replace everything in the coolig system, I mean everything! When the boat is idoling aroung the marina or no wake zones my temp is 150-160 degrees, but when up on plane and running my temp is 180-190 degrees. My alarm keeps going off and its driving me crazy. I think I need a lower unit with low water pickups in the drive, I currently have standard pickups for water. Has anyone ever had this problem or heard of it. Thanks

[DON N.]

IS THERE A SMALL HOSE WHERE OUT DRIVE PICKS UP THATS GETTING PINCHED OR RESTRICTED ? IVE HEARD OF PEOPLE CHANGING HOSE TO A STRAIGHT ONE AND THEY PINCH OFF. IF THIS IS THE CASE GET THE ONE THATS MADE FOR OUT DRIVE .

[MOP]

When was the last the exhaust risers were inspected, I would not think the water pickup would not make a difference if all is stock.

[RickR]

If the supply hose on the transom bracket is not pinched, install a (temporary) piece of clear hose before the thermostat (drive side) and see if you get any bubbles (sucking air)

[Rootsy]

My system is set to alarm @ 180 F... if you are ok while idling or cruising but begin to overheat at high rpm you most likely have a restriction or weak impeller...

[MOP]

Rick brought up a good point on air getting into the system. You can suck air in from quite a few places, drive grommets, drive hose and even inboard. Check all you clamps. I found leaks many times at the oil cooler, intakes on sea water pumps, many did not show a leak but a speed sucked air.

[KennyD]

Check the outer pump housing, there has been a problem around my marina with a bunch of parts being bad from the maker. They leave just a little gap when you think that it is sealed. This is enough to cause a vaccum leak which will do just what you have described. Idle or low rpm no problem, high rpm OVERHEAT.

[RICPAZ]

I have the low water pick-up on my outdrive with my 502 and I haven't had any over-heating problems. With your standard water pick-ups you shouldn't be over-heating at low to mid-range speeds. The advatntage of the low water pick-ups would probably only be noticed at really high speeds or W.O.T.

-Rich

[HyperDonzi]

Did you break 75?

[fasttrucker]

I would install a seastrainer from teaque marine.You can get one that matches the paint job on your boat.They really help supply water when your outdrive gets out of the water.Plus they are cool,you can see the water spining around.Also if you do run into seaweed it keeps it out of the motor. wink

[Lil Grizz]

Several things here could be wrong.
#1 you could be sucking air from somewhere
#2 your circulating pump or sea pump or both could be defective. Just because its new doesnt mean it isnt faulty.
#3 Wrong, defective, or incorrectly installed thermostat.
#4 Debris in the system
#5 Faulty sensor

I had an upper end overheat problem which turned out to be a combo of a non-opening thermostat and a large chunk of rust that looked like a rock clogging up the housing. For the money I would install a water pressure gauge so you could know exactly when and how you were getting the problem. Too much pressure will just as easily cause an overheat as too little pressure. Why jump to the most costly and unnecessary solution if you dont need it? Low water pickups are great and all but since a transom mount works worse than what you have right now your only option is to get a new lower or have yours sent off to have pickups added on. This usually requires a nosecone so your looking at a minimum of $350 and that more than anything still wont cure your problem.

There is another way, cheap if you do it yourself, to take the standard bravo pickups and put them deeper in the water. What you do is tap threads into the upper two or three holes on each side and put in some plugs. drill new holes under the bottom inlets (still in line with the others). Its actually not too difficult and fairly effective. costs less than $10 bucks for the parts. Unfortunately I doubt its going to fix your overheat.

[Donzi22zx]

Thanks For all the help guys, I have changed the sea water pump 3 times in the last year, flushed out the block, had the thermostat housing glass beaded and installed new sensors in it. I replaced the thermostat 3 times as well, installed new exhaust manifolds and oil cooler, but still have the problem. I am at a loss and no expert I have talked to has the right answer. I installed a water pressure gauge, but have not hooked it up yet, will be doing so this week, what is the proper pressure. I talked to a guy at the Bravo shop and he told me that on step bottom boats this is common and recomended low water pick-ups in the drive. I did not know that they just came out with them in late 1999. I hope to fix the problem soon. As for the speed I have had bad weather lately and have not gotten it out for a test run.

[Lil Grizz]

Have you checked the circulating pump? I removed mine in favor of a crossover system. Its also possible that there is somthing between the drive pickup and sea pump restricting flow. Its also possible that the hose connecting the drive to the transom has gotten a hole in it so all the water just blows out and you suck air.

[Donzi22zx]

I also replace the circulating pump at the end of last season, I was going to add a new Hardin marine serpentine belt crossover set up. The hose might have a hole but I do not think so, when I use the garden hose to flush it I do not have water leaking anywhere. Do you have any pics of your engine setup,Drive. What is your best speed on GPS. Thanks Bill

[MOP]

I've seen one blade of a pump flipped back the wrong way in a housing from it being turned the wrong way after assembly. That was a tough one, all else was fine. Found that going back in to the drive check the water tube grommet, decided to check the new pump! What was fun it was a new boat! "Warrantee"! :D

[fasttrucker]

My 502 is ready for the install after the upgrades my pro meck. has made.Hes putting on a low water pickup/lower unit that he took off another performance boat.I didnt tell him to do this,he just took it off the other boat.He told me he was putting it on my boat.So i think maybe you are right in looking to get one.This may not fix your overheating issue,but it cant hurt.When are we going to hook up this year for a little run. :p Are you near the c+d canel in de.?

[Ed Donnelly]

I should have learned by now,not to offer my opinions.But here goes.. Have you checked your timing lately. I had the same problem a couple of years ago. Anything over 3000rpm overheated like crazy. Found my timing at 40 Degrees set back to 36 and the problem went away...Ed

[Lil Grizz]

Ed Donnelly:
I should have learned by now,not to offer my opinions.But here goes.. Have you checked your timing lately. I had the same problem a couple of years ago. Anything over 3000rpm overheated like crazy. Found my timing at 40 Degrees set back to 36 and the problem went away...Ed Plug gap can do the same thing if too wide. You bring up a good point. Also the headers can sometimes cause a lean condition which possibly could cause an overheat.

[Forrest]

Lil Grizz mentioned someting a few posts back that you should take a good look at if everything else looks good, and that is debris in the block or other cooling passages. One time I had a pencil zinc break off and and get caught in the circulation pump which caused all kinds of problems with overheating while underway. I finally found the problem but only afer spending a ton of time going through all the standard problem areas.

[Moody Blu']

ahhhhh cooling problems :mad:

if your thinking about changing all that stuff you might want to consider a transom pick up instead.