1979 Evinrude 40 hp bogs down sporaticly

[Guppy]

I bought a 1979 Evinrude 40 hp motor and the first time I took it out it sparaticly boged down or cut out. Started good did not idle even on fast idle. Runs better at slower speeds. Compression 140 and 135. Spark plugs look new but one was wet. When I checked the compression it looked like there might have been some fuel coming from cylinder. One last thing the lower cylinder does have gas coming out when spark plug is out but not top cylinder. Pulled wire off of power pack, i think that is what it is called, and there is black grease packed in the end.

 

[12Footer]

Re: 1979 Evinrude 40 hp bogs down sporaticly

Welcome to iboats, Larry. Check for spark.<br />Buy a spark checker from the auto parts store for about 8 buks, or make one using an old plug and a hose clamp. Two cautions when checking for spark at the plug..First, be sure the other end is grounded, because leaving a plug wire off the plug or floating freely, will kill the CD ignition. Second, give it a wide berth durring testing, as the arc can jump a 1/2" air gap, and sometimes, even more than that! It hurts bad to be hit by this lightning.<br />But I suspect this is the problem (missing ignition to one or cylinder), and could be caused by plug, trigger, switchbox, coil or plug wire.<br />Not 100% positive of that, but going by your description, my best guess.<br />(One wet plug, one dry + wont idle + poor performance together = missing one one lung )<br />The '76 I owned ate coils for lunch, so it would be where I would look first,if she were on my transom.

 

[Guppy]

Re: 1979 Evinrude 40 hp bogs down sporaticly

Thanks for the info. There is no change in motor rpm or sound when I pull off and replace plug wirers. Will pick up a plug tester.<br />Thanks for the help.

 

[OBJ]

Re: 1979 Evinrude 40 hp bogs down sporaticly

Hi Larry.<br /><br />On the other end of the stick, lets look at fuel system. You could be having trouble from a flooding carb. Any idea the last time the carbs were over hauled? Take a look at the gaskets between the float boal and carb. If the gasket is black, you probably definitly need a carb over haul. The newer carb gaskets are made from Vitron which is a rubber that resists todays formulated gas. They don't tend to dry out and get brittle like the old black gaskets. Knowing how long the rig sat before you bought it would also help. Look at fuel lines and replace any that are hard and have lost their flex. By all means thourghly check out the ignition system as was suggested by 12footer. And by all means, get a manual. A OEM manual is the preferred weapon against bugs in the motor. Keep us posted and Good Luck!

 

[sailor_turned_stinkpotter]

Re: 1979 Evinrude 40 hp bogs down sporaticly

Hi Larry Fish,<br /><br />Are you sure its gas coming out of your number two cylinder?<br />If its water, then that is your problem.<br />Water is probably ingressing through the power head base, or head gasket and causing your described problems.<br />An easy way to check is hold your hand in front of the spark plug hole while its running until enough liquid condenses on your hand and then figure out whether its water or gas, but i dont think it would be gas.<br /><br />good luck,<br />dave.

 

[Guppy]

Re: 1979 Evinrude 40 hp bogs down sporaticly

It is gas just a fine drops it even burns. No idea how lonmg it set. I do know it was at the dealers less than 180 days. <br /><br />Maybe this will help remimber the last time you were out on the lake and ran out of gas in a 6 gal tank. The motor dies and then picks up and then dies well mine never dies just bogs down and then takes off. It might do this once in a mile.<br /><br />Thanks to everyone who is trying to help!