5.7 MIE (TKS) issues...

Ok... it starts and runs ok until the enrichment circuit times out. Then there is a very brief period when the engine runs a bit rough, then it smooths out. So far, so good. However, if I open the throttle slightly in gear or out, the engine stalls. If I open the throttle abruptly, enough to get fuel from the accelerator pump to squirt, all is ok.
The only problem is that while in gear, you can't get the engine to run between idle and about 1100 rpm without pumping the throttle continuously.

I took the top off the carb and all appears to be OK with the accelerator pump and the carb is clean.

BTW... cost saving tip for TKS carb owners... smear a very thin film of grease on both sides of the air horn to bowl gasket before installing it and when you take the air horn off next time, the gasket ( ~$20) will survive and be reusable.

Have you tried adjusting the idle mixture screw yet?

Merc has a special tool to adjust it, Part number 91-866201.

Do you have service manual number 41 that covers this carb?

The reason i say try adjusting the idle mixture is because recently someone else's boat was running about the same as yours, And he had the TKS also, But his boat was still under warranty, So I told him to go have it looked at before his warranty expires and he came back on the forum to say his dealer said they adjusted the idle mixture screw.
And he said his boat run much better now, So it might be worth a shot.

Good luck with it.

boat_tech said:

Have you tried adjusting the idle mixture screw yet?

Merc has a special tool to adjust it, Part number 91-866201.

Do you have service manual number 41 that covers this carb?

The reason i say try adjusting the idle mixture is because recently someone else's boat was running about the same as yours, And he had the TKS also, But his boat was still under warranty, So I told him to go have it looked at before his warranty expires and he came back on the forum to say his dealer said they adjusted the idle mixture screw.
And he said his boat run much better now, So it might be worth a shot.

Good luck with it.

Click to expand...

Just got the manual and tool yesterday, so will be trying that today.
Thanks for the feedback, hopefully I'm on the right track.

So far... blew out the passages and a piece of crap "appeared" in the bore....mmmm
Also... found out the both the float drop and height were waaay off from the specs in S/M #41. When it cools off some this afternoon I'll give it a try.

Got over there this afternoon and installed the carb... Ran much better, but still no cigar. When it starts and finishes the idle enrichment phase, I can now not only open the throttle without stalling in neutral, but I can out it in gear without stalling... however, in gear a soon as I open the throttle, it starts to stumble and wants to stall. More twiddling with the mixture seems to be in order. I know you have to put the engine in base mode to set idle and idle mix, however, I didn't have a "handle" for the mixture tool and tried to adjust using just my fingers on the tool. No fun to say the least and I quit in frustration. I'll root around the basement and see if I can find a suitable handle for it and try again in the a.m. It's usable as it stands, I just need it to be well behaved.

"however, in gear a soon as I open the throttle, it starts to stumble and wants to stall"

The stumble means the accellerator pump circuit is not functioning properly; not enough full coming from the pump. Some carbs have accell. pump linkage adjustment holes in the cam lever. Did you put it in the right hole upon reassy.?

Put link on the center hole...which is default per manual.