idle - starting problems

[willxuout]

Hello<br /><br />I have a 1996 Evinrude 225 hp v6 looper carbed outboard. The powerhead was recently rebuilt and has about 15 hours on it. I am now pre-mixing my oil a 50:1 (used 25:1 during breakin).<br /><br />Here's the problem...I have had idle problems from the very beginning after the rebuild. It will prime and start fine and idle for a couple of minutes and the shut off...it will start right back up. The motor has a new VRO pump, stator, totally rebuit carbs, primer bulb and fuel lines. I just had the 10 hour check up with a different mech and he said the motor in great condition...even compression on all cylinders at 100...the timing was 1 deg retarded and he suggested that we leave it there...I check the plugs frequently and they look just right (light coat of oil and medium brown in color) there is no buildup on the plug surface indicating a lean or rich condition. Anyway, the motor just doesn't want to idle in or out of gear...it idles at 900 rpm and then stumbles to 700 rpm and then dies...it starts right back up...sometime it will go into gear and run PERFECT...most of the times it just dies.<br /><br />Also, after we run the motor for about an hour going out to the fishing spot and we sit for about an hour...we will have to reprime the build to get the motor to start...otherwise it will just crank and crank.<br /><br />Any ideas about what the problem is?<br /><br />Thanks

 

[ezeke]

Re: idle - starting problems

Check for possible air leak on the fuel supply.

 

[AUGIDAWG]

Re: idle - starting problems

Advance your idle timing that 1 degree. My 95' 200 looper idles at 2 degrees "BEFORE" top dead center. If I retard it, it runs the same way you describe, except, mine will re-start fine without pumping the bulb. I have my carb idle mixture screws turned out 4 turns.<br />I talked to a mechanic for almost an hour yesterday about the idle timing being out of spec. (suppose to be 0-4 ATDC)<br />He said, don't worry about it. He makes sure the carbs are closed, to insure it is running on the idle circuit, and then turns the idle timing adjustment until it idles at the right rpm. Then, he adjusts the idle screws until he gets them dialed-in, then adjusts the idle timing screw again, and never bothers checking the idle timing again.<br />He said, it won't hurt the engine to be a little too far advanced below 2500 rpm, but, the WOT timing must be right on, or you will cause engine damage.<br /><br />Try the QL78YC plugs if you are not already using them. My motor idles better with them than the QL77JC4. I'm also gapping them at .033"

 

[kclark1963]

Re: idle - starting problems

I had the same problem with 2000 Johnson 115 and it turned out to be an o-ring in the vapor pump I'm not familiar with your engine I hope this helps. <br /><br />Kevin

 

[ezeke]

Re: idle - starting problems

The fact that you have to re-prime and the inability to idle together indicate an air leak. <br /><br />For your own peace of mind, disconnect the fuel line between the pump and carb at the pump, temporarily attach a piece of clear tubing, and look for air bubbles while running.

 

[willxuout]

Re: idle - starting problems

AUGIDAWG:<br /><br />Hey, thanks for the info...I'll have the mech advance the timing on the idle circuit...by the way, I've only had to reprime on the last time out...every other time before this the motor will fire right off after stalling.<br /><br />I'm also going to use a piece of clear tubing to check for air in the fuel line...just to make sure.<br /><br />I'll post the results later.<br /><br />Thanks

 

[willxuout]

Re: idle - starting problems

Forgot to mention...the motor only acts this way in the water (back pressure)...on the muffs it will idle forever.<br /><br />Thanks again.

 

[AUGIDAWG]

Re: idle - starting problems

The engine runs much leaner on the muffs.<br />May want to lean out your mixture screws 1/2 of a turn.<br />Also, I think the manual is wrong as to where the timing should be with the boat warm, idleing in gear.<br /><br />In my opinion, with the carbs fully closed, warm and in gear, the roller not touching the throttle cam (.005" clearance), adjust the idle timing screw until you get 650-700 rpm. Now your timing will not be within spec. It will be advanced a little more, like 2 degrees BTDC. Now, when you put it in neutral, the engine will rev up to 900-950 rpm. This is not good, because it slams when you put it in gear. Now, adjust the idle throttle linkage stop to lower the idle to 650-700 rpm. You may have to adjust the linkage to get it to touch the stop. Check your timing. It will be 0-4 degrees ATDC. (within spec) So, now when you put it in gear, it will be too retarded. You have too push just a little on the throttle until it idles at 650-700 rpm (timing is advancing), but the carbs are still closed.<br />You are done.<br />It will idle all day and shift fine.<br /><br />Remember, I am just a rookie, but it works for me.<br />The manual is wrong in other places.<br />I have read and re-read the whole sequence on "sync-link", and it doesn't make sence. A engine with no load will idle higher than a engine with a load, if the carbs are closed, and there is the same gap between the roller and the cam (idle timing/carb syncronization).

 

[R.Johnson]

Re: idle - starting problems

When this engine was rebuilt, did they change, or replace the recirculation valves?

 

[Dhadley]

Re: idle - starting problems

It almost sounds as if the idle was set while the motor was in the Quick Start mode. Or while running on the hose (no back pressure as you mentioned). Make sure they are setting the idle in the water with the motor out of QS.<br /><br />Good luck!

 

[AUGIDAWG]

Re: idle - starting problems

I thought mine was in the "QuickStart" mode. I did much trouble shooting the QuickStart, and the system is working perfectly. But if I follow the book, it will either idle fine in neutral (in the water), and will die after 10 seconds in gear, or, if I advance it, it will idle too fast in neutral, and just fine in gear, and the timing ends up 2 degrees BTDC to keep it running.<br />It could be that the carbs aren't brand new, the compression isn't like a brand new engine. But, anyone buying a "repair" manual, is most likely working on a used engine. In the idle timing/idle speed section, it doesn't say, "If you can't get the timing within spec, rebuild the carbs, or check the compression". It says, "Go back and perform the link/sync again."<br /><br />Now, if it is suppose to be when you put it in gear, and the throttle box hits what feels like an indent, the timing linkage advances a little while the carbs are still closed, that would explain that I have not done something right. BUT, that means that the timing is NOT at the specified 0-4 ATDC, while warm, in the water, in gear, unrestrained like both the Clymer and factory manual states.<br /><br />I may take it in to the shop and make the guy a bet that he can't do it as the manual states.

 

[93bronco]

Re: idle - starting problems

AUGIDAWG<br /> i would really like to get a detailed way on how you lync/sync through to idle timing. if its not to much trouble. i think is worth checking for me. thanx

 

[willxuout]

Re: idle - starting problems

Dhadley:<br />I took the motor back right away the the original mech put it in a water tank and reset the idle with some backpressure on it...the idle rpm's were now in the right spot.<br /><br />It's funny that someone would mention the recirc valves...supposedly they came installed on the rebuilt powerhead...but the mech who put everything back together took the old recirc valves off the old powerhead and put them on the new powerhead...said the new ones didn't work? Anyway, I checked the upper and lower valves that run from the lower crankcase to the upper crankcase bearing...those bearings are working fine...should I go ahead and check the others?<br /><br />I assuming recirc valves that don't work will cause the problems I'm having...right?<br /><br />I've had two different mech check the Linc and Sync and they say It's right.<br /><br />Could the problem be in the throttle cable adjustment?

 

[StillFishin']

Re: idle - starting problems

I had a 115 that I rebiult and reused the old recirulationg valves and I always had idling problems. Never could get it right. When that pwerhead blew, I put new recir valves and hoses on and it idles great. So I think those valves are important to a good idle. Also check the hoses for cracks or leaks.<br /><br />StillFishin'

 

[willxuout]

Re: idle - starting problems

I just talked to the mech...he said change the plugs out first to eleminate the simple stuff. We have been running 25:1 during breakin and have run 50:1 the last two trips<br /><br />We'll try the fresh plugs...he suggests the L77JC4 plug...I'm running the 78's right now with 87 octane.<br /><br />Any thoughts...should I stick with plug model I'm using now or go to the 77's?

 

[AUGIDAWG]

Re: idle - starting problems

2K Boat,<br />Just follow the manual until it says, "With the motor running at the specified idle speed in FORWARD gear, check the idle timing. Idle timing should be as follows,,,,(it has a chart for different engines)" Then it says, "If the idle timing is not correct at the specified engine speed, recheck all linkage adjustments and repair as required." (this is where I think they are wrong)<br />Now, in my opinion, put the engine into NEUTRAL, and check the timing. It will be the same as in FORWARD gear, too far advanced and out of spec. Now, do NOT adjust the idle timing screw. The relationship between the carbs being closed, the .005" gap between the roller and the cam, and the idle adjustment screw, while in FORWARD gear, must stay this way. Instead, turn the throttle linkage stop screw counter-clockwise, until the idle drops to the specified rpm, in NEUTRAL. This retards the timing to the specified value without changing the relationship to the carbs. You may have to adjust the throttle cable length to keep the stop screw in contact with the engine block. The gap between the roller and the cam in NEUTRAL is now much greater than .005". It doesn't matter.<br />Now, your engine will idle at the specified rpm, when you first move the throttle forward into gear, the rpm will drop below the specified rpm, but it will shift smoothly and gentley, then move the throttle a little more until it idles at the specified rpm (timing has advanced, but carbs are still closed). If you don't move the throttle a little more, it will die after about 15 seconds, because the timing is (within spec) too retarded.<br />Now you can troll all day and keep your gearbox from being damaged.

 

[93bronco]

Re: idle - starting problems

here is a statement out of an omc manual<br /> Important- <br />a disfunctional recirc system will cause one or more of the following operational symptons:<br />-erratic or poor idle characteristics<br />-fouled spark plugs in lower cylinders<br />-excessive smoke when accelerated after extended idle<br />-idle quality unusually sensitive to trim angle<br />-----<br />if it was my motor i would have him put 6 new recirc fittings (1 for each intake port), new check valve(s) & all related hoses.<br />-<br />your mech should know better.<br />are you sure he even rebuilt the carbs or did he cut those corners & reuse them too?

 

[willxuout]

Re: idle - starting problems

2k boat:<br /><br />I'm sure he rebuilt the carbs...I was breathing down the back of his neck while he was putting everything back together.<br /><br />I agree with you on the recirc system...one of the guys on this board emailed me the recirc system procedures awhile back...I think I'll replace the valves as suggested.<br /><br />I'll post the results back here within a couple of weeks.<br /><br />Thanks

 

[willxuout]

Re: idle - starting problems

2k boat:<br /><br />I know were the 6 recirc fittings are on the block and am aware of only one inline check valve between the lower crankcase and the upper crank bearing housing. As far as I can tell there is a rubber hose from the rear of the carb housing that runs to the recirc valves. I didn't see any other inline check valves...am I missing something?<br /><br />Thanks for everyone's help!

 

[93bronco]

Re: idle - starting problems

augidawg thanx<br />-<br />didnt mean to ask augidawg a ?? on your issue, it was just a good point.<br />-<br />you have the 6 drain fittings on the back sides of the of each cylinder with hoses going to 6 recirc fittings on sides of each intake leaf ports.<br />then you have the upper & lower bearing hoses with the check valve in between. make sure that its arrow is pointing up to upper bearing. that will be the direction of flow.<br />-<br />then there appears to be 6 internal check valves but the intake has to be off to remove them for those tests.<br />-<br />hope that helps