omc running temp

[vicsponjr]

I havew a 88 Four Winns 215 Sundowner, 5.7 w/Cobra. temp goes up to about 190 running at 3800 rpm's. At that point I slow it down and the temp comes down. Is this normal, or do I need to pull the manifolds/risers. Impeller was changed.

 

[rbezdon]

Re: omc running temp

vic, not normal. Mine gets to just over 175 when running hard and about 170 to 175 all other times with a 160 thermostat (based on dash gauge). 190 is too hot for a marine engine. I would check water flow through manifolds risers and block (open block drains).

 

[vicsponjr]

Re: omc running temp

open block drains??????

 

[Lou C]

Re: omc running temp

Mine runs right at 160 about all the time, 190 is definitely too hot. You can take the hose from the transom to the thermo housing off temporarily and start the motor with the boat in the water, it should shoot a column of water up in the air several inches. When you did the impeller did you replace the housing and wear plate? The housing must be well sealed or the pump can pull in air when it is on plane. <br />Make sure the risers/manifolds are not blocked with rust, if they have been used more than 5-7 years you may need replacement.<br />The other thing to check is to make sure the thermo opens up all the way, they sometimes get sticky when they get old.

 

[rbezdon]

Re: omc running temp

vic, there should be two valves tapped into the block, one on each side just below and behind the front motor mounts. These valves are meant for draining each side of the SBC V8 block for winterization. I open these periodically and let water drain from then into the bilge. Some times I have to screw the valve part all the way out and push a piece of wire in there to "free" up some of the sediment that gathers in the bottom of the block. I dont know how much of it I get out but I do it anyway. Figure it cant hurt to flush some of that crud out of the block. Just make sure you close em up when you are done or they'll fill up the bilge. By the way, the holes for these drains are in all SBC including cars but on cars they just put plugs in them.

 

[vicsponjr]

Re: omc running temp

Ron,<br />OK, I know what drains your talikng about, thanks. The block is fairly new, but it won't hurt to drain it. <br />Lou,<br />I thought that housing would be a problem. That impeller change was too easy. When I went to replce the housing I couldn't get the new o-ring in place, like it was too small, so I re-used the old one. After assembling it I attached the hose and there was a little seapage coming from the housing. I'll pick up a pump kit and replace the housing. <br /><br />By the way Ron, the boat is DEFINATELY not for sale!!! <br />Put the esa module in and its shifting pretty nice. Just have to get it running cooler, which doesn't seem to be a problem, even if it needs risers and manifolds. <br />Other than that, just got to move the axle on the trailer before last pull out of the water, toungue weight too light.

 

[cobra 3.0]

Re: omc running temp

I had a similar problem on my 3.0. Changed the impeller, temp sending unit and cleaned out all the hoses, the manifold and riser. Still had the same issues of temps suddenly rising for no apparent reason.<br /> <br />Finally, I suspected the guage may be the cultprint, so I bought a complete car temperature guage at Walmart($12.00 Can) and hooked it up to see that the engine temp was indeed ok at 160F with no issues. It was a cheap and effective way to finally isolate the problem.

 

[KaGee]

Re: omc running temp

Cobra, you lucked out that your guage matched your sender.

 

[danthern]

Re: omc running temp

I too have a 5.7 litre OMC. My manual says that the thermostat doesn't completely open until 190...??

 

[Lou C]

Re: omc running temp

That must not be an OE manual....<br />they start to open at about 155-160<br />fully open at about 175 or so....<br />I have to change em every 2 seasons, raw water cooled in salt water<br />I check em in a pot of boiling water on the stove with a car thermostat thermometer, the new ones respond faster and open wider than the used ones do, so my take is the thermostats get sticky over time, at least in salt water.

 

[vicsponjr]

Re: omc running temp

I took the impeller out again and replaced the wear plate and gasket. Put it back together and hooked the hose up, engine not running. Still a little water coming out of the housing?????

 

[rbezdon]

Re: omc running temp

vic, on my 88 Cobra if on the muffs with the engine off the only water i get out of the leg is around the muffs where there is too much water flow because the engine is off. I get no water around the water pump. Sounds like you still have a problem up there.

 

[vicsponjr]

Re: omc running temp

took it out today and it ran at about 175. Works for me, at least till end of season when I plan to remove and inspect the risers and manifolds. I'll probably take the whole pump assembly apart then too. There was a good bit of corrosion around the wear plate, I'm sure there's more back there if I keep digging.