evinrude 25hp baxckfire problem

[sxm_tj]

Hi
ive checked with the search but stil not sure,

my 25 hp evinrude with breaker points backfires of sneezes on the 2nd cilinder, cilinder number 1 is fine, the problem is only with cilinder number 2 with low rpms and when i give some gas, it stops with WOT.

ive cleaned crabs troughlt, ive checked every part from the egnition

thanks in advanced greetz
Tjeerd Goslinga

 

[tashasdaddy]

Re: evinrude 25hp baxckfire problem

does it backfire like a gun, or just cough, if cough, follow these directions.

http://forums.iboats.com/showthread.php?t=167352

 

[sxm_tj]

Re: evinrude 25hp baxckfire problem

when it backfires on the lower cilinder it gives i big sputter drops in rpm and gains back again, you van zee in my fuel filter wich comes from the pump that there is exces presure like aa sneeze in the fuel filter.

i know about the needle adjustment, but im not sure if this is the problem, seeing its only on the lower cilinder?
greetz

 

[kbait]

Re: evinrude 25hp baxckfire problem

I've had a pinhole in a plugwire do weird things... g'luck,kirby

 

[HighTrim]

Re: evinrude 25hp baxckfire problem

First adjust as per the link TD supplied.

Spitting back, sounding like a mild backfire, indicates a carb slow speed restricted jet..... something causing a lean carb scenario.

Remove the carb face plate. With the engine running and with that coughing condition existing, stick two fingers into the carburetor throat that is acting up, this acting as a choke sort of.

If the rpms increase a bit and the cough goes away, this would indicate an idle air bleed jet that has a slightly too large ID.

I would also check out the spark just to rule that out.

 

[F_R]

Re: evinrude 25hp baxckfire problem

If you can't find anything wrong with the fuel system, consider a possible leaky lower crankshaft seal, admitting air to the lower cylinder and resulting in a lean sneeze of the lower.

 

[sxm_tj]

Re: evinrude 25hp baxckfire problem

If you can't find anything wrong with the fuel system, consider a possible leaky lower crankshaft seal, admitting air to the lower cylinder and resulting in a lean sneeze of the lower.

thats what i was thinking to, wel il check that out, just waiting for alotta free time

 

[whywhyzed]

Re: evinrude 25hp baxckfire problem

h......

 

[sxm_tj]

Re: evinrude 25hp baxckfire problem

i identified it by taking the spark plug off the bottom cilinder, result was it ran on only the top cilinder and was not sneezing
as soon as i hooked up the bottom spark plug it started sneezing, could it be a leeking seal?

greetz