115 evinrude spark no power ?

[kodibass]

I have a mid 80's 115 e-rude, it has 110 compression on all 4 cylinders, and good spark on all 4 jumps a good 7/16 gap on all 4 cylinders. when running if I pull the spark plug boot off of the strbd cylinders there is a noticeable change in rpms, but when I pull a boot off the port plugs there is no change at all ? So does this mean the port cylinders are not getting fuel? I'm not sure how the carbs deliver fuel to these v motors I thought that the top carb sent fuel to both top cylinders and the bottom carb sent fuel to the bottom cylinders is this correct? Anyway something don't seem right any thoughts/help most appreciated I have very little experience with the bigger motors this one was a free-bee.

 

[Bosunsmate]

yes thats it but the carbs have two bores one feeds port one feeds starboard, a blockage in the port side jets etc would cause that but i expect youd be hearing a backfire/lean sneeze if that was the case.
Pull your plugs, note any colour difference, then clean your plugs then turn the engine over for five seconds with the sparkplug wires grounded (or your safety line disconnected).
Remove plugs, Check that your port bank plug tips a wet with fuel, compare them to the starboard side

 

[Bosunsmate]

Also check that none of those port cylinders look clean- ie waters getting in there.
If all that checks ok then move on to timing

 

[racerone]

What colour stripe is on the top orange wires on the coils ?

 

[kodibass]

The coil wires are plain orange, there are two wires coming out of each coil one going to a connector harness and the other going to ground at the coil bolts the ones grounded behind the coils are orange with a black stripe, the other is plain orange, when I went to check I noticed the port coils are of a different type than the starboard they are flatter shaped coils and are all black, the starboard side are black and gray and thicker (more rounded) shaped so I think the port coils are not original, They do fire my spark checker tho, ? I will try the spark plug check & look for wetness also.

 

[Auxlarry]

Racerone asked this because the Primary coil wire on these engines are orange and orange with blue stripe. The Orange/Blue always goes on the top coil!! Make sure they are this way or that bank won't fire properly!

 

[kodibass]

Ok i'LL look again further up the wire to see if I can find the blue stripe, I noticed that the spark plugs are much darker than the ones on the starboard bank ( blacker) but I did ground them to the block and they are firing when I crank it over, so If I can't find the blue stripe can I just switch plug wires ? I am going to try and barrow the manual for this motor from a friend & keep at her. thanks

 

[Auxlarry]

Yes, you can switch the plug wires!
Are the plugs wet when you pull them out?

 

[kodibass]

Great news! that was indeed the problem the coils were backwards , switched them and now running on all four. Still idles a bit ruff but I think that is most likely dirty carbs I'll take them off and give them a good cleaning, Thanks to all'' as I said this is my first V engine that I have messed with so I don't know much about how they work, Heck I don't even have a boat to put it on yet but if I get it going good I'll find something. :joyous:

 

[Bosunsmate]

cool, just keep an eye on the temperatures of each head, if a thermostat is seized or theres a blockage in the cooling system she will blow her rings.
And dont run her long if shes missing/misfiring as she will like be lean from carb issues and boing will go her rings again.
Apart from that its a great motor so dont put her on anything that sinks