Idle Help Evinrude 85HP

[DoingTheBestICan]

Hey all, Wondering if you can give me some advise on a problem I have.

I have an Evinrude 85HP 1972 Hydro Electric Shift Motor. Things that has been done to it is. New fuel pump, new power pack or power amplifier, carbs have been completely cleaned and new gaskets put in, new spark plugs. Lower unit has had its routine maintenance,Impeller, gear oil changed regularly. I have spark on all plugs and compression is 103 on 3 cylinders and 99 on another.

Here’s the issue. I have to advance the throttle to get it to crank and choke it. I usually keep it at fast idle till it warms up then start slowing it down. It’s an old motor so I baby it to get it started. Since I went through the carbs and changed fuel pump etc it dies when I slow down to a slow idle speed .

Is this just an adjustment that I need to make like the idle screws ( I’ve tried that) or is there something else I need to be looking at ?

Thank you for any assistance,

 

[racerone]

Remove flywheel.---Clean distributor cap and rotor.----Inspect anti-reversing spring.---Clean and set breaker points to 0.010"----There are no idle mixture screws shown on that model.----Your compression is low , but try another gauge first.

 

[F_R]

Hey all, Wondering if you can give me some advise on a problem I have.

I have an Evinrude 85HP 1972 Hydro Electric Shift Motor. Things that has been done to it is. New fuel pump, new power pack or power amplifier, carbs have been completely cleaned and new gaskets put in, new spark plugs. Lower unit has had its routine maintenance,Impeller, gear oil changed regularly. I have spark on all plugs and compression is 103 on 3 cylinders and 99 on another.

Here’s the issue. I have to advance the throttle to get it to crank and choke it. I usually keep it at fast idle till it warms up then start slowing it down. It’s an old motor so I baby it to get it started. Since I went through the carbs and changed fuel pump etc it dies when I slow down to a slow idle speed .

Is this just an adjustment that I need to make like the idle screws ( I’ve tried that) or is there something else I need to be looking at ?

Thank you for any assistance,

So you tried adjusting the idle screws? If you mean the four screws up front near/below the choke plates, well there ya go, those are not idle screws. They need to be turned all the way in, with gaskets under the heads.

 

[F_R]

Got any idea why only 90 psi on that one cylinder? Has it been overheated in some time in the past? We saw lots of damaged powerheads due to failed water pump impellers in nearly new motors back in "The Day"

 

[jimmbo]

72 was the First year for the Fixed Low Speed Jets. What is the Model # of your engine?

 

[DoingTheBestICan]

72 was the First year for the Fixed Low Speed Jets. What is the Model # of your engine?

the model number is 85293R

 

[racerone]

Test compression with another gauge.----Or remove bypass covers to inspect piston / rings.

 

[jimmbo]

That number does check out as a 72.
Just out of Curiosity, what speed are you trying to get it to idle at?
When you put the carbs back on, they are correctly synced with each other, and with the timing?

 

[oldboat1]

The motor may be slowing as it warms up due to rich running. Try using the choke manually (choke knob on the port side of the lower engine cover. Pull it out to cold start, raise the fast idle lever on the remote box.) Push the knob back in (may need to feather it a bit). Lower the fast idle lever. At that point, you should be able to advance the throttle slightly, if needed, with the control handle. I it's warmed up and otherwise running well but stalling out at too slow an idle, you may need to adjust the remote throttle cable to hold at a slightly higher idle. (Remove the cable at the motor and adjust the motor setting, then reattach the remote cable to match using the daisy wheel to adjust as needed.)