head gasket ? '77 evinrude 85

[DaMoos]

I have a '77 evinrude 85. Seems to run well at higher power settings, but is a little rough at idle, sometimes makinmg it difficult to get into gear without stalling. It seems to do better cold than hot.

I recently changed the plugs, which seemed to help a little.

I have white smoke at idle, comming from the two holes on the rear of the engine, just below the lower cowl. I assume these arer the tell tale holes, as they are hooket to two rubber hoses coming off of the heads. A spatter of water comes out of these holes at idle. No smoke that i can see at WOT.


I inspected the impeller, and it is in new looking condition.

I thought maybe white smoke meant I was running rich, but I recently read here that it is potentialy steam from a blow head gasket.


Is a head gasket job a cheap and easy task? Is it still possible i'm running rich at idle?

I haven't checked compression yet, but will as soon as I can get a compression gauge.

 

[ScottinAZ]

Re: head gasket ? '77 evinrude 85

the v-4's arent that hard to do a head gasket on. I think I did mine in about 2 hours start to finish. Just make sure to follow the torque specs, and to get the gasket surfaces clean before installing the new gaskets. I had similar issues with running like crap and stalling at idle, and a new pair of head gaskets solved the issue. IIRC, gaskets are about 20-25 a piece.

 

[emdsapmgr]

Re: head gasket ? '77 evinrude 85

The two ports on the top of the midsection are exhaust relief holes. They assist the engine to idle. Once the thermostat (vernatherm) opens, you should get a fine mist out of them at idle. Check your compression before you decide the head gaskets are the problem. You could have debris in the idle passages of the carb bodies.

 

[DaMoos]

Re: head gasket ? '77 evinrude 85

I do plan to check compression first, if anything just to get a before and after reading if i do the gasket change.

If an idle passage was blocked, wouldn't I run lean at idle? Why then the white smoke?

also, when I look into the spark plug ports with a flashlight, 3 piston heads look normal, and one looks squeaky clean. That and the fact that after the motor has been running a bit, the idle problem gets worse. Wouldn't all these factors suggest head gasket? If it still sounds like a carb issue, is it time for a rebuild?

Is the t-shaped object where these idle exaust relief hoses meet my thermostat?

 

[emdsapmgr]

Re: head gasket ? '77 evinrude 85

Yes, a clean piston top can indicate water intrustion into that cyl. The water will wash it clean. Water intrustion can come from a bad head gasket, also-a leaking exhaust cover gasket. Exhaust water leaks tend to affect the lower cylinders more. The thermostat housing is at the top of the midsection-one hose from each head dumps water into it.