Information: All Cylinders not firing

[mthieme]

The following is specific to 4 cylinders Mercury outboards 100 1988 & on & 115 HP 115 and on 2+2 system.

So all your cylinders aren't firing...don't tear the powerhead down yet...

The two lower carburetors have in a delay of the off-idle circuit below about 1,800 rpm.
Above 1,800 rpm the two lower carbs operate normally.
The two upper carbs have idle mixture screws, the two bottom ones have a permanent plug. It is important that the carbs be mounted in their proper positions.
At speeds below about 1,800 rpm only the No. 1 and 2 cylinders fire normally. Cylinders 3 & 4 are supplied with too lean a mixture to burn (but does contain enough oil for adequate cylinder lubrication).

 

[Laddies]

Re: Information: All Cylinders not firing

This info does not cover any 4 cyl. engines built before 1988.

 

[mthieme]

Re: Information: All Cylinders not firing

Can you elaborate.
I'm transposing some common troubleshooting & procedural info for the shade trees - I wanna get it right.

 

[Laddies]

Re: Information: All Cylinders not firing

Thats the bad part of imported info from a source that your not sure of, the engines that someone is talking about are the newest series of 4 cyl Mercury's the first of which was the 100 HP built in 1988 and the info about the carb spacing is not right either, the bottom 2 carbs not supplying enough fuel to run but enough to lube the cyls at idle is right however. The earliest 4 cyls were built in 1949 the model KG-9, 25HP and were close kin of the 40HP 4 cyl last built in 1996. I did not respond to your post to belittle you but there is far to much wrong info out there.

 

[mthieme]

Re: Information: All Cylinders not firing

thanks.
I've modified the initial post slightly after a little more research.
Evidently, I have a little more to do...trying to find more info on this 2+2 system isn't so easy.

I have a neighbor with a KG-9 in his shed...been sitting there for 20 years.
I'm close to getting him off of it. These are extremely coveted hydroplane motors.

 

[Laddies]

Re: Information: All Cylinders not firing

The KG-9 is a very coveted engine and was rated at 25HP as a embarrassment to the 25HP Jrudes, if it has the original squeeze grip throttle handle it's really a find. Good luck in the obtaining and restoring of it. If there is any info I could help with on the 2x2 engines with PM me.

 

[mthieme]

Re: Information: All Cylinders not firing

I just want to make sure what I have there is accurate.
Just the general idea of how it works is good enough to get the message across.
Is the rpm range accurate?

 

[Laddies]

Re: Information: All Cylinders not firing

Yes, usually a little slower but it verys depending on the engine set up.

 

[mthieme]

Re: Information: All Cylinders not firing

I appreciate your help.
This was intended to be a more generic thing...got in over my head a little on this one.