low speed idle problem on 1979 Johnson 175

[brianinGalveston]

I am having problems with the low speed idle and was wondering if you had any advice.<br /><br />Prior to putting the boat into the water I was able to drop the start lever to a low idle and the motor would continue to run. But when I put the boat in the water, I could not drop the start lever down without the motor dieing. I could raise the start lever up and the RPM would climb as expected. When I got home I tried to drop the start lever down again, but it died too. I’ll try it again when I get home (thinking it is a hot/cold kind of a thing).<br /><br />Any suggestions are greatly appreciated.<br /><br />Brian

 

[Yepblaze]

Re: low speed idle problem on 1979 Johnson 175

It's time for you to do the "diagnostic procedure".<br /><br />If you feel like you want to tackle it yourself, it could become involved and you should have a manual at hand.<br /><br />Pull the plugs, do a compression check.<br /><br />Get back to us on what the compression is in each cylinder, look at plug color and condition, and get back to us.

 

[brianinGalveston]

Re: low speed idle problem on 1979 Johnson 175

I think it is due a tune-up at best, the boat has been sitting for a while. Heck, I got the boat for free, so putting some money into it is not out the question.<br /><br />I'll try your suggestions.<br /><br />Thanks,<br />Brian

 

[janichol]

Re: low speed idle problem on 1979 Johnson 175

Something else to look at... the idle is supposed to be set with the boat in the water unrestrained (good flow over the lower unit). I had the same problem with a 200 Oceanrunner when the idle was set low (and the idle spark retard rod was bent). Ran fine (1100 rpm) on the hose, died in the water. Start at about 1100 RPM out of the water and see how it performs in the water from there.

 

[brianinGalveston]

Re: low speed idle problem on 1979 Johnson 175

Scudrunner,<br />Hello neighbor. I am not sure what the idle speed should be set at, but I have the manual on the way and I guess it should tell me. But like I said, when I was at home I could set the start lever all the way down and it would idle at ~800 RPMs. But on the water I could not get it below 1000 RPMs.<br /><br />I will look at the idle spark retard rod....whatever that is. I can't wait for the manual to come.<br /><br />Brian

 

[ob]

Re: low speed idle problem on 1979 Johnson 175

Brian , In your first post you say that the motor will idle on the hose at and when you put it in the water and lower the idle arm it would die.<br /> In your last post you say it idles on the hose at 800 but it won't idle below 1000 in water. If the first post is accurate bare in mind that these are exhaust tuned motors and a partial carb restriction of porting or pickup tubes will dramatically effect the idle in and out of water.In general a 2 stroke will idle a bit higher(200 rpm or so) on the hose than when submerged in water.Gummy carburetors are quite common problem on infrequently operated 2 strokes.<br /> I personally have never seen a 2 stroke motor condition where it idled higher in water than on the hose.<br /> I believe your motor has an idle stop screw.Around 1000 on hose is ballpark and 850 in gear idle in water.Make sure your throttle cable and carb linkage has freedom of movement and not sticking.Insure carb flaps are closing fully and equally in nuetral throttle position and are opening fully horizontal in WOT position.

 

[brianinGalveston]

Re: low speed idle problem on 1979 Johnson 175

Well, I can't get the start lever all the way down before it dies, in or out of the water.<br /><br />With Christmas and a seven year old, it is slow going checking everthing you've suggested.

 

[brianinGalveston]

Re: low speed idle problem on 1979 Johnson 175

OB, let me clairfy. I could not get the motor to idle with the lever down while in the water. When I dropped the start lever down the motor would die around 1000 RPMs.<br /><br />Hope this helps.<br /><br />Brian