73, 125hp evenrude doesn't idle

[paperdesk]

Re: 73, 125hp evenrude doesn't idle

Hey Ledge, you hit the nail on the head! That really describes it well.<br /><br />The carbs look like they were rebuilt fairly recently, but I didn't open it all up (looked really time consuming) to check. I will try to do a good decarb on them though.<br /><br />I'll try to fix my tachometer and check my rpm's.<br /><br />Do you have any tips on how to check the sync?<br /><br />I have NKG plugs in there I think. When I pulled them they had a fair ammount of crud (carbon?) on them. I could scrape it off with my finger nail.<br /><br />Finally, I don't think it sounds like I'm running on less than 4 cylinders, but I'll listen for that.<br /><br />BTW, how does the "power pack" I keep reading about play into this? What does a power pack do?<br /><br />Thank you all for posting and helping get this baby into excellent shape. I want it to last!

 

[R.Johnson]

Re: 73, 125hp evenrude doesn't idle

Going from top to bottom, cylinder's on the right are 1 & 3, on the left 2 & 4. What the pulse pak does is that it receives about 350 volt's from the charge coil under the flywheel. When triggered it send's this 350 volt's to the ignition coils. They in turn send 30,000 + volt's to the plugs. Thats why when you get in contact with a plug wire you feel like you've been welded to the floor. Use champion plugs in your engine, no other.

 

[paperdesk]

Re: 73, 125hp evenrude doesn't idle

Anyone have explination of how to check the sync? This seems like the next thing to do. Does it require "open engine" surgery? Or, maybe just lifting the head?

 

[SCO]

Re: 73, 125hp evenrude doesn't idle

Gotta make sure the throttle linkage is set up right first. Will be detailed in the service manual.

 

[paperdesk]

Re: 73, 125hp evenrude doesn't idle

where can I find a service manuel? Do I need to look at one at a dealer's shop?

 

[OBJ]

Re: 73, 125hp evenrude doesn't idle

Hi Ted....just read through the entire thread. It would sound from yer original post that this engine is "new" to you?<br /><br />Your compression readings are in the park as was posted but good decarb as suggested would be a good idea.<br /><br />Check the spark. Rig a tester that has a gap of at least 7/16". Each cylinder spark should jump the gap with a hot white lightening like spark. <br /><br />How is the engine temp? A cold running engine will make idle a nightmare. At idle, you should be able to lay your fingers on the flat area above and just forward of the heads for a few seconds without jerking them away. If they feel cold after the engine has run for a while, the t-stats may need replaced. Your engine will not idle well cold.<br /><br />Check the fuel lines. Replace any that are hard and have lost their flex. A hard fuel line loses its grip and can suck air. Not a good thing. Same for the fuel line to the engine. And make sure the tank vents properly.<br /><br />Carbs may look good on the outside but it's the inside that counts. What's the color of the float bowl gasket? If a redish brown color, then you will know that they have been rebuilt. The original gaskets were black and do not hold up well with the newer reformulated fuels. I would still consider taking a peek inside the carbs.<br /><br />Keep us posted to your progress...thanks.

 

[paperdesk]

Re: 73, 125hp evenrude doesn't idle

Hi OBJ. Yes, I just bought the boat and motor. I've only taken it out a couple times so far.<br /><br />I'll check the spark as soon as I can get someone help me turn the engine while I check. <br /><br />I never thought of checking the temperature. I'll definately do that ASAP. Sounds like an easy test anyway!<br /><br />I wondered why people were talking about replacing fuel lines. Now I know! I know that the line coming from the tank isn't real tight, and looks old. I'll see about replacing everything that looks like it needs it.<br /><br />I started getting to the carbs, but it looked like such a big project! Would have to disconnect so many things! I might have a pro look at the carbs for me unless I can get ahold of a service manuel. I don't want to mess anything up. <br /><br />Guess I'll just go down these fixes one at a time till I fix the problem.

 

[paperdesk]

Re: 73, 125hp evenrude doesn't idle

All this is getting a little over my head! I've taken the boat to a dealer to have a look at it. I'm also ordering a service manual. I'll let you know what happens!<br /><br />Ted

 

[DJ]

Re: 73, 125hp evenrude doesn't idle

Ted,<br /><br />A few items.<br /><br />1. That 135 was never a really good idling engine, however it can be made to be tolerable.<br /><br />2. Decarb that engine-now!<br /><br />3. Get those NGK plugs out of there. Use only Champions in an OMC (John/Rude) product.

 

[Dhadley]

Re: 73, 125hp evenrude doesn't idle

Ditto -- no KGB plugs in an OMC!!<br /><br />Just a note -- as mentioned, when everything is perfect, those motors still didnt idle all that well. We used to put 115 heads on them and they idled great! And on a recreational boat you couldnt tell the difference on top end.<br /><br />Just some trivia.

 

[paperdesk]

Re: 73, 125hp evenrude doesn't idle

DJ the other day I tried to do a decarb but for some reason I couldn't get the motor started. I figured I'd better let someone look at it and fix my little tinkerings with the choke and idle.<br />Since I couldn't even get it started anymore I got worried. I'll let you all know what they say.<br /><br />I also tried to get champion plugs and they didn't have them in my small town. I'll persist, and order them if I have to though!<br /><br />Thanks for the advice and info. I know that between the shop, me, and you guys, we'll get it going well!

 

[paperdesk]

Re: 73, 125hp evenrude doesn't idle

KGB plugs. Just got it hehe. Good one!