Idle/start problems '73 Johnson 135 v4

[SCO]

Re: Idle/start problems '73 Johnson 135 v4

Learning all the time. By george I think I've got it. Not sure because the engine must cool for the test sometime tomorrow. I looked at the throttle cam, and readjusted it, but found it was very close to procedure. I then read the idle set instructions on the carb covers(had been buried in the service manual prior to this) where it said to unhook the throttle control cable. I found it screwed too far in, such that when you pull the neutral throttle lever, the effect was to uncoil the throttle control cable rather than moving the throttle. I reset that and all of a sudden I had a lot more throttle capability with the neutral throttle lever. It s looking good, and in effect I've been trying to start at near the lowest throttle setting. Joe Reeves said the throttle might be too low, and is proven correct in this respect, and hopefully in all respects if the motor starts well tomorrow. Will post with the results.

 

[SCO]

Re: Idle/start problems '73 Johnson 135 v4

The problem still persists.I put the boat in the water this morn and it took twice as long to start firing as on the flushette. At least we are ruling out a lot. I got a few more pieces of the puzzle today. <br /> 1) it is clearly having a difficult time getting fuel into the cylinders. It took 12 seconds to first fire in the water vs 6 sec on flushette. , then a long time to start running. Thought I was going to run down the battery. I think the back pressure reduces the intake suction<br /><br /> 2) The motor is making a new noise while cranking , and intermittent loud short SHHH sound, usually at the end of a crank . Is this a leak through the reeds? <br /><br /> 3) I am concluding it has to be a suction/leak problem. Do you all agree. What do I do from here. Junk the motor? <br /><br />I'm frustrated but will do what ever it takes to get this motor to run right.

 

[Pst76]

Re: Idle/start problems '73 Johnson 135 v4

SCO, I have read your post and I have exactly the same issue with a 74 115. Spent all last year messing with it going through same test and rebuilds and all. Hard to start first try but once running. no problems rest of the day. I could start with muffs much easier. I even tried starting with muffs to warm up and then drop in the water. As soon as I put back pressure on the exhaust in the water it was like it was never started. Almost seemed like I had to crank forever to build pressure. But like I said ran all day. Once also after running I put back on trailer and let sit. Backed boat back into the water and tried to restart. Same sinario just as though it had not run all day. I spoke with one mechanic who said he thought that one of the ring sets on a few cyl's that draw in on the down stroke was loosing the compression. Doing a regular test showed 90 to 100 lbs but he said that would not confirm intake pressure. Not sure if I bought that but I gave up on the motor. In the process of replacing as we speak. No fun at the launch when theres a line .<br /><br />Good luck

 

[SCO]

Re: Idle/start problems '73 Johnson 135 v4

Hello pst, <br /><br />You had it worse than me, but very similar. If I start on the flushette just prior, it will start in the water. But, it is worse than when I first got the engine. One cyl has always had a little less comp, at 120 psi, and maybe I ned to rebore. I am going to get this thing working, it's just a machine. I am thinking now of a workaround, squirting premix in the carbs to see if I can jump start it. If that doesnt work, I am ready to tear it down. Once started, this motor just runs great, and the running idle is good now that I have advanced it some. I have a '58 18 hp and 14 foot alum to tide me over. Keep suggesting all, and thanks for all opinions and impressions right or wrong. I'd like to hear anything that pops into anyones mind no matter how obscure.

 

[jim dozier]

Re: Idle/start problems '73 Johnson 135 v4

I've been reading your saga here. I was wondering if at any point in this you have tried squirting premix gas into the carb throat. If that helps you would at least know if you were lacking fuel. If it doesn't you can start looking at other things (I have to squirt gas in my lawn mower every time I want to use it). For what it worth whenever I lose my car keys I usually find it in a place I've already looked (inadequately) twice.<br /><br />OOPs, I just read your last post and I see we are on the same wavelength.

 

[jim dozier]

Re: Idle/start problems '73 Johnson 135 v4

Is it possible that your idle jet is adjusted just a little too lean. It may be idling well but for good acceleration and easier starting you usually have to enrichen the idle circuit a bit beyond best idle. Just a thought.

 

[SCO]

Re: Idle/start problems '73 Johnson 135 v4

Jim, I do think the premix will work, and that is the next procedure, though I think the machine should work as designed. It will verify the fuel problem but still wont prove it is not a carb problem. I'll report immediately on that test, robably late sunday. <br />BTW, it takes me some 10 pulls on my honda lawnmower to start also. I think it has a leak somewhere. Thanks for your posts and keep them coming.