Evinrude overheating

[LaurenceWeissbrot]

I have an Evinrude 160 HP outboard. Vintage 1985.<br />It has been running hot, to the point where the high temperature horn sounds after a few minutes under load. Runs fine attached to a hose in the yard.<br />Replaced water pump impellor. Cleaned water jackets. There was a large buildup of salt on the side of the gasket away from the engine. Cleaned that, but it still overheated. Removed thermostats.<br />Removed heads to be sure water passages are clear. Still overheats.<br />I'm guessing that sufficient water is not getting up to the engine.<br />Is there a place where the water line from the pump might be leaking? Is there anything else that could be causing this?<br />It is not the oil horn.<br />Thank you.<br />Laurie

 

[wilde1j]

Re: Evinrude overheating

What size is your motor? I didn't know OMC made a 160 in 1985.<br /><br />You may need to drop the LU again and force water into the water tube to make sure water passages are clear. But first make sure it's running hot. Can you keep your hand on the cylinder heads when running w/ the cover off and the hot horn has sounded? (Watch out for burns!)<br /><br />Also, are you sure the water tube enterred the pump adapter AND the grommet didn't get distorted in the process. I usually clean up the tube end w/ sand paper, put a little grease on the tube before replacing the LU. Also, I put some hardening Permatex on the grommet and allow it to dry first. This keeps it in place as the water tube enters the adapter.<br /><br />Further, did you replace all pump parts or just the impeller? If the wear plate is scored, you won't get max capacity from the pump.

 

[Justin Sims]

Re: Evinrude overheating

SOUNDS LIKE THE WATER PUMP IS SUCKING AIR. TAKE IT BACK APART A PUT SOME ADHESIVE SEALER AROUND THE BASE OF THE HOUSING WHERE IT FASTENS DOWN TO THE THE WEAR PLATE AND TO THE CASTING.

 

[Dhadley]

Re: Evinrude overheating

There are 3 little rubber deflectors on each side of the block in the water passages. Are they still there? And in good shape or kind of squished out and flat?<br /><br />Good luck!

 

[LaurenceWeissbrot]

Re: Evinrude overheating

The little deflectors are in place and in good shape.<br />I'll have to wait for the weekend to try dropping the LU and checking the water pump. <br />The water pump was checked, and the impellor replaced, by a professional boat mechanic. When that didn't work, he asked me what to try next!<br /><br />Thanks to all who have responded so far. New places to look.<br /><br />Laurie

 

[Dhadley]

Re: Evinrude overheating

The professional asked the customer what to do? Who paid who?<br /><br />When you say it runs fine on the hose (not overheating, right?) that tends to make us think the problem may lie in the pump. As suggested, if he only replaced the impeller, that may be the problem. Replace the entire kit and use a good quality kit. There are some aftermarket brand impellers that have had some hub bonding problems. Thats not to say there are not good after market impellers available. What brand did he use?<br /><br />Keep us informed!

 

[LaurenceWeissbrot]

Re: Evinrude overheating

Further information.<br />Sorry for the typo -- it's a 150 longshaft.<br />Mechanic rebuilt entire water pump. Used sealer around the flange.<br />He's suggesting the overheating is caused by a scored cylinder wall. Possible?<br />Water does shoot out of the weep hole.<br />Any other suggestions?<br />Thanks,<br />Laurie

 

[Dhadley]

Re: Evinrude overheating

Rebuilt the water pump? I hope he replaced it. And again -- what brand?<br /><br />You mentioned salt build up. Were the water jacket covers removed from the heads and passages cleaned? Thermostats still removed? Pressure relief valves OK?<br /><br />?????

 

[LaurenceWeissbrot]

Re: Evinrude overheating

I live in CT and work during the week in NH, so I can't check the repair slip to get the brand until the weekend.<br />Yes, opened the water jackets. There is a gasket that separates the water jacket into two chambers: one on the engine side, one on the cover side. The engine side was fairly clear. The cover side was almost solid with salt. <br />Thermostats are still out, and pressure relief valves are in place. Assume they're functioning.<br />Removed thermostat covers at one point to check water flow (originally thought one side might be plugged). Water flowed out both sides. Question -- how much water should flow? Should it gush? Should it be under pressure? It was a steady trickle, but I have nothing to compare it against.<br />In answer to the question about how hot the engine got: used a surface pyrometer (again, originally looking for a difference between left and right sides) and the outside surface of the water jackets got up to 145-150 degrees F. Before cleaning out the salt deposits, the temperature gauge wasn't reading that hot even when the alarm was sounding. After cleaning out the salt, the temperature gauge was in the red. So the sensor for the gauge is in the outer water jacket, while the sensors for the horn go deeper into the heads.<br />Also, besides running with the hose, removed the prop and put the lower unit into a barrel filled with water to see if it would pump on its own. It did. Ran OK (didn't overheat) for half an hour.<br />Only seems to happen under load.<br />When running on the hose, I tried to look for places where water might be leaking. There is what looks like a tube going up the very front part of the lower unit. Water was running down around this tube. Is there a connection that might be leaking before the water ever gets to the engine? Or is this just spray from the "ears".<br />The mechanic reminds me it was overheating before he replaced the water pump, and he didn't think the pump was the problem in the first place.<br /><br />Laurie<br />I THINK I have now included every piece of useful information. <br /><br />Laurie

 

[Greg Lawrence]

Re: Evinrude overheating

btw most johnson outboards have their water outlets at the bottom of the water jackets. Plugged theold water outlet and I moved mine to the top by drilling and tapping a hole on top of the head and sealing it up real good, now im sure no bubbles will ever form.