I have an Evinrude outboard that starts fine out of the water with ear muffs, but won't start in the water????

Question

Any thoughts on what is going on? The plugs are getting fuel, and the choke is moving as it should. Bought new plugs tonight and am going to see if that helps int he morning. One last question, what is the difference between a marine spark plug and any other? Thanks in advance!

Answer 1

Hi, 1st, spark plugs for marine use are for specific motor temps and have better corrosion resistance. The sparking portions my be different to allow for clearance.

2nd. while out of the water, your boat is on a trailer - nice and flat. On the water, it is tilted substantially.

Has someone hit the engine cut off switch?

You said that you are getting fuel but does it go thru a water / fuel separator first? How old is the fuel hose, is it flooding with no spark? Is it starts then dies? Are you getting a spark? - Take out a plug, put it back the sp boot, put on a rubber glove or hold it with some rubberized handled plyers, place next to engine block and have someone turn the key for you. You got spark - then most likely you have an issue with the fuel delivery.No spark - check neutral switch - check wiring - . Hopes this helps.

Answer 2

This sounds like a compression problem.  If it starts fine out of the water but can't fire when prop is submerged, this could be a serious problem.

You need to do a compression check first on all your cylinders before trying anything else.  If you don't have a compression guage, you'll need to get one.

Also, you need to take your outboard's HP, model, year, serial number and model number to an OMC dealer or service shop and ask them for the compression data for it.

Ask them what is optimal, what is okay, and what is bad?

If you find out your outboard has compression issues, you need to take it to an OMC tech and have it checked out.  This may or may not require a rebuild.

Otherwise, if compression is okay, then this might be an ignition system problem.

Answer 3

your motor calls for one type of plug and thats what you use  as for why it doest start in the water

i dont know

Answer 4

what year and horsepower?

don't use any plug not recommended in your manual.  and especially don't use a plug not designated as "marine".  johnnyrudes run best on champion plugs, the NGK equivalents aren't an exact match for heat range.

now, around the back side of your motor, just below the powerhead, are two holes - those are "exhaust relief ports".  When the underwater exhaust is submerged, it puts backpressure on the engine making it difficult to start -- the relief ports relieve some of the pressure to make starting easier.

Those ports need to be above the surface of the water for starting.