Engine will not stay idling

[g_speran]

Hello ALCON,
I have a Mercruiser 3.0, serial #0B698339, and I can not keep the engine idling/running. I am looking for the service manual for this so that I can start troubleshooting. I have looked at http://boatinfo.no/lib/library.html# and http://www.marineengine.com/parts/s...ngine.com/parts/sierra_marine/sierra00580.htm . I probably am overlooking it but I can seem to locate my serial number for the engine in them.
I am assuming that since my boat is a 1987 Suunbird Corsair, the at the engine is a 1987 as well. but I could be assuming incorrectly

If you have a link to the proper service manual for my engine so that I can download it, that would be fantastic as well. I am looking a doing a necessary tune-up this weekend so I am trying to get my ducks in a row.

I will be reading :

• How To: Troubleshoot a Points Ignition System - http://forums.iboats.com/showthread.php?t=335407
• How To: Tune-up Your Engine with Points Ignition - http://forums.iboats.com/showthread.php?t=335302
• How points ignition system works - http://forums.iboats.com/showthread.php?t=329742&p=2186518#post2186518

I will report back to this forum once I am successful in keping the engine running.

TIA,
Gary

 

[Don S]

Re: Engine will not stay idling

Manual #10 is the one you want from boat info.

I would suggest you check the carb as well. Plugged passages will prevent idle.

 

[g_speran]

Re: Engine will not stay idling

Thanks Don...I guess this is were my confussion began. I looked at Service Manual 10 and on page 3, located at http://boatinfo.no/lib/mercruiser/manuals/mercruiser10.html#/2 , I see the 3.0 but it stated 0C856450 and above. With mine being 0B698339, I ruled it out.

Since you are stating to refer to SM #10...I will do so.

TIA,
Gary

 

[Don S]

Re: Engine will not stay idling

The serial number you posted is for the drive, not the engine.

 

[g_speran]

Re: Engine will not stay idling

OK...now I am really confused. I have attached the images as well for clarification

these are the 3 stickers on the Engine. Which one is the SN for the engine?

 

[g_speran]

Re: Engine will not stay idling

dang...I think I posted the right picture...wrong SN. I believe the SN should be B727015 for the engine. Therefore is Service Manual 10, still the correct one?

TIA,
Gary

 

[Don S]

Re: Engine will not stay idling

Yes, 10 is the correct manual. The engine is an 87.

 

[g_speran]

Re: Engine will not stay idling

you ROCK man!!!

Thank you for all the responses you do for us newbies!

TIA,
Gary

 

[g_speran]

Re: Engine will not stay idling

OK, so here is a bit of an update.

Yesterday, finally, I was able to start working on it again. I disconnected the fuel line from the Carburetor and then unscrewed the connector inlet, revealing the fuel strainer. This strainer was 98% full of CRUD. Therefore, I cleaned the CRUD out of the strainer and completely removed the carburetor so that I can clean it. As suspected, it needed cleaning as it was MAJORLY corroded (pictures attached). After a successful cleaning and putting it all back together, I re-connected the fuel line. With a single turn of the key...vroom...vroom....vroom.....it fired right up. I let it run for over an hour, and then shut it off. I fired it up several more times throughout the day with no issues....this is when the fun ends.

Images Prior to cleaning


Today, I went to fire it up?and it fired up on first turn of the key, but within 30-45 seconds, it shut down and cant fire it up again. So again, I removed the fuel line, removed the connector inlet, revealing the fuel strainer. The fuel strainer, this time had sand like debris in it.

A while back, I had removed the fuel pump, cleaned it out the best I could, as it was majorly gummed up from sitting over 3 years, and replaced the filter in it. I believe it had the paper filter and may have been replaced with a ceramic filter.

1) Is it possible that I need to clean the fuel pump again?
2) Re-clean the carb again?

Also, I noticed
1) The goldish color choke valve, in the Airhorn assembly just flops down, nothing to keep it closed and nothing preventing from keeping it opened. (To be true, I have no concept on how the electric choke mechanism works?it?s like a magical thing to me :facepalm: ). This was today while the carb was connect properly. Now that the carb has been removed, it has spring (Back in its step ) , again, closing the choke valve.
2) After keeping the key turned for 15-20 seconds, fuel starts coming up out of the carb, in the location identified on the image attached.

Thoughts, advice, help?

Thanks
Gary

 

[Maclin]

Re: Engine will not stay idling

Fuel coming out of there indicates the needle and seat is not closing off enough to keep fuel at the level specified by the fuel bowl float setting. The needle and seat could be compromised again, or the float could be not floating because it is full of fuel, or the level setting is wrong.

It sounds like you do not have the water separating fuel filter setup between the tank and the fuel pump. That will catch a lot of debris first, should be changed yearly, installing one is a good upgrade to perform. If all you have for filtering is the small cartridge in the carb inlet then you will be replacing it often until all the junk has had a chance to flow thru.

 

[g_speran]

Re: Engine will not stay idling

Hello All,
I have time to revist this again. I have completly cleaned and rebuild the carb. I can start the enginge with no problem by disengaging the thottly and placing it slightly forward. I've let it run for about 30 minutes like this. I then try to move the throttle back to the Neutral position and the engine starts to die.
I followed the "tips" in the manual by "backing out on the screw until it no longer contacts the cam (boat not running), turn screw back in until it just touches the cam and then two additional full turns, then go about adjusting your idle mixture screw setting by seating it and then backing it out 1 1/4 turns. ". However, my defination of "seating it" may be different than what what is meant. Can someone explain this?
I have also tried adjusting the the mixture screw while I have my son bring the throttle back to neurtal position by turring the screw clockwise; This seems to want to make the engine die faster.

Any thoughs/recommendations that would help in making this engine idle?

 

[ktbarrentine]

Re: Engine will not stay idling

What was your RPM during the 30 min run? What is the RPM when it "starts to die?" Does the choke plate close fully when cold (after a pump of the throttle to set it)? What is condition of the choke plate after a few minutes of running (should be wide open by then). Can you see anything flooding the carb when you try and take it back to idle (specifically the area you showed before, and also the port from the sight-flow tube)? Is the engine timing set correctly?

 

[g_speran]

Re: Engine will not stay idling

No sure to any of the questions that you have asked. WHen I get home this weekend, I will see if the RMP gage is working and I will take the Carb cover off to observe the choke plate functionality

Thanks
Gary