Mariner 115hp 2+2 only fires on 2 of 4 cylinders

[underwaterflorida]

I have a 98 Mariner 115hp 2+2 outboard that only fires on the top 2 cylinders. The bottom 2 cyl never kick in at 1800 rpms or at any rpm like they are suppose to. The
bottom 2 cyl's get spark and will fire if I spray starter fluid in them. I rebuilt the bottom 2 carbs, new fuel lines, filters and still no fire. I followed the fuel through the
engine and the bottom 2 carb bowls will fill with gas, they just never suck the fuel from the bowl into the intake/butterfly.
What would be the cause of the fuel not sucking from the bowl into the body/throat/butterfly?

 

[gbrowne9]

Re: Mariner 115hp 2+2 only fires on 2 of 4 cylinders

check the acelerator pump below the throttle cam. see if it is injecting fuel into the bottom 2 cyl's through the smaller fuel lines that run to the other side of the block. the acel pump gives the bottom 2 cyl's the fuel needed to get up to speed.

 

[FLATHEAD MAC]

Re: Mariner 115hp 2+2 only fires on 2 of 4 cylinders

:facepalm: READ A POST THE OTHER DAY person had w.o.t issues . rebuilt carbs in found out that they accidently installed a gasget wrong, small hole in gasget was not lined up with hole in carb flange , might bouble check.

 

[underwaterflorida]

Re: Mariner 115hp 2+2 only fires on 2 of 4 cylinders

Thank for the tips. Took apart carbs again, making sure there are no blocked passages. Took apart accelerator pump, it's working fine. Gas flows to all carbs. Bottom 2 cyl's still do not fire. Checked coils, are fine. Bottom 2 cyl's
fire w/ starter fluid. Compression is 100 on all 4 cyl's. I'm stumped at this point.

 

[underwaterflorida]

Re: Mariner 115hp 2+2 only fires on 2 of 4 cylinders

Fyi.. Just sea tested and everything works. Not sure what part failed but I guess rebuilding the carbs and cleaning them for a 3rd time did the trick.

 

[Texasmark]

Re: Mariner 115hp 2+2 only fires on 2 of 4 cylinders

Fyi.. Just sea tested and everything works. Not sure what part failed but I guess rebuilding the carbs and cleaning them for a 3rd time did the trick.

Well thank you sir for sharing your success with us because this is the only payment we get for trying to help fellow boaters enjoy boating more.

Mark