overheating engine ( stumped with no help)

[ferrariman]

Hi , my name is elliott and i am rebuilding a 1989 industrial version 25 hp 2 stroke johnson. I have put many new parts in my motor including a waterpump and the motor runs great all through to WOT. But it over heats quite quickly and i can put my finger on what it is. If you have any ideas please drop a line. Thnx

 

[emdsapmgr]

Re: overheating engine ( stumped with no help)

Does the engine have a strong telltale of water shooting out of the lower cowl? Did you also replace the thermostat-always should be part of any rebuild.

 

[OBJ]

Re: overheating engine ( stumped with no help)

Welcome aboard Elliot!<br /><br />Is this a new motor to you?<br /><br />Is it pumping any water at all?<br /><br />Did you put a new t-stat in it?<br /><br />Did it overheat before putting in the new water pump? During re-assembly, are you sure you got the water tube in the water pump housing gromment without mashing over the grommet?<br /><br />Sorry for all the questions.....just trying to get a little more info and narrow the cause down.

 

[ferrariman]

Re: overheating engine ( stumped with no help)

this motor is very new to me the only other motor i have rebuilt before was a 1954 evinrude fleetwin. Everything that has to do with the impeller and pump housing and whatnot is all in good shape i had help from a pro. There is very good water flow and judging by how this motor is preforming aside from the overheating i dont think that a leaky head gasket is to blame. Most people i have talked to have said it is probably the thermostat that needs replaceing as it was used in salt water.

 

[DHPMARINE]

Re: overheating engine ( stumped with no help)

Through the years I can't tell you how many 'good' looking impellers I've replaced and had it solve an overheat problem.<br /><br />Also are you aware of the defectors located in the water passages around the cylinders,under the cyl head?If not check the partss book for them.<br /><br />DHP

 

[ferrariman]

Re: overheating engine ( stumped with no help)

I have replaced the impeller and all other parts to do with the water cooling system and i was supervised by a specialist who double checked everything and nothing was put in wrong. At the time all fingers seem to point to the T-stat.

 

[ferrariman]

Re: overheating engine ( stumped with no help)

I am a greenhorn when it comes to outboards. Do you think you could tell me what a defector is?

 

[mikeyzx2]

Re: overheating engine ( stumped with no help)

They're just little rubber pieces that are placed in certain locations of water jacket so that the water can only flow in one direction.

 

[OBJ]

Re: overheating engine ( stumped with no help)

If you don't know what kind of shape the t-stat is in, it would be a very good idea to pull the head cover plate and take a look. Being that the engine was used in salt water, you would want to clean out the passages under the head cover anyways. Referring to the other posts, it would probably be a real good idea to pull the head completely and check the deflectors. This would also make it easier to remove the head cover plate and replace the t-stat. The deflectors, as Mikey stated, are just rubber tubes that keep the cooling water flow going in the right direction.

 

[mikeyzx2]

Re: overheating engine ( stumped with no help)

Oh, and you asked what DEFECTORS are? They are those that switch from OMC's to Mercs. Just kidding, as I have the trifecta, an Evinrude, a Johnson, and a Merc.

 

[DHPMARINE]

Re: overheating engine ( stumped with no help)

Sorry,guess I owe you an 'L'<br /><br />Vanna <br /><br />Actually don't the defLectors hold the water in hot spots so the water absorbs the heat before moving on?Back around 1986 or so,there was a bulletin about them being missing on some motors.<br /><br />DHP

 

[OBJ]

Re: overheating engine ( stumped with no help)

I knew there was something strange about you Mikey....... <br /><br />I tried finding that bulletin on the deflectors DHP but came up empty. The PartSmart program don't have all of them I'm thinking. If nothing else, the deflectors ensure the the water flow gets to the hot spots.

 

[mikeyzx2]

Re: overheating engine ( stumped with no help)

DHP, that would be interesting about missing defLectors. I actually didn't catch the missing "L" in you post. <br /><br />OBJ, I gots a question while I'm on this post. I really need to check out my 'stat also, but the darn bolts are rusted up. Should I go with the Craftsman Bolt Outs to remove them, and God forbid what would I need to do should a head break off? What are the specs on these bolts, ie length, diameter, threads?<br /><br />HOOK 'EM HORNS!!!

 

[OBJ]

Re: overheating engine ( stumped with no help)

Mikey....you got mail.

 

[mikeyzx2]

Re: overheating engine ( stumped with no help)

Thanks, I'm checking it now......good luck with you motor ferrariman!

 

[DHPMARINE]

Re: overheating engine ( stumped with no help)

OBJ,<br /><br />It took some doing,but I did find that bulletin on Partsmart.It's B 2215,Inconsistant Cooling System Operation.<br /><br />DHP

 

[OBJ]

Re: overheating engine ( stumped with no help)

HAH!....looked at it and it didn't register first time around.....thanks DHP!.....