Can't get the port engine to fire

[Ed Whitlock]

I bought the boat this year, and have had no issues, except until the last trip. 1988 Sea Ray Sundancer, twin 4.3L Mercruiser 6 cylinder engines with thunderbolt ignition. The last trip, the port engine was hard to start, but finally caught, and we got underway. It started to overheat a little, but caught it and lowered the idle to get the temp right. Later found out that it was a bad water pump, and has been replaced. The next morning, the engine started, but cut out at low idle, and will not restart. I have verified that there is spark at the distributor and on eah cable, using a timing gun. Rebuilt the carb, to make sure it was not a fuel air mix problem. replaced the spark plugs. Still will not start. It sounds like it wants to start, but won't.

Also, there is a buzzing noise coming from the bottom of the engine with the key turned on. There has never been a buzzing noise there before, and no buzzing noise from the other engine, which starts with no issues. It sounds like it is coming from the front starboard side of the bottom of the engine.

I have a video of me trying to start it, and will post it once I get it uploaded to the computer.

Any ideas?

Ed

 

[Ed Whitlock]

Oh, yeah, after replacing the carb, verified that it is getting fuel. So it is not an air or gas problem. And with the spark at the distributor cap, which I also replaced, is not a spark problem. Is there some cut out thing?

dang video is too large to upload, but have placed a link to it to my google drive.

Thanks

Ed

https://drive.google.com/open?id=1iPV7pTA_k40EVrUcQh72EoiIcIL3rpzs

 

[northern]

Long ago with old cars we used to pour gas in the carb to get them to start. If you have spark and new carb I would look at the fuel pump. Not really good idea to pour gas in a carb on a boat as BOOM may happen. You may want to consider replacing fuel pump or have the one you have tested. New one is $100 a mechanic is $100 an hour. So new fuel pump might be least expensive.
Your starter sounds a little weak either batteries or it needs a rebuild perhaps.

 

[PlayDate]

Nice video....sounds like a timing issue. Do you have the bilge fan tied into the run wire on that engine? That would account for the buzzing sound.

 

[Ed Whitlock]

Long ago with old cars we used to pour gas in the carb to get them to start. If you have spark and new carb I would look at the fuel pump. Not really good idea to pour gas in a carb on a boat as BOOM may happen. You may want to consider replacing fuel pump or have the one you have tested. New one is $100 a mechanic is $100 an hour. So new fuel pump might be least expensive.
Your starter sounds a little weak either batteries or it needs a rebuild perhaps.

It sounds weak, but have two batteries (one brand new) on that side of the boat - have 4 batteries in total on the boat, cross connected through the battery charger, and that is connected to pier power right now.

Is the fuel pump electric on these, or mechanical? Not too sure of all the bits and pieces yet. Took me a while to find the petcock for the AC system.

The fuel flow is pretty good, in that once I opened the isolation valve to the fuel tank, I had gas squirting through the carb into the intake manifold.

Thanks for the info!

Ed

 

[JimG]

Could the buzzing be an electric fuel pump?

 

[Ed Whitlock]

Nice video....sounds like a timing issue. Do you have the bilge fan tied into the run wire on that engine? That would account for the buzzing sound.

The buzzing is totally new to me. The bilge fans are on their own circuit, and did not even have them on for the starting, since I have had the covers off for a while trying to work on the engine.

Do you (or anyone) know the proper setting for the timing on these engines? I can check the timing, since I have the timing light right there in the bay - I was just using it to verify that I have spark.

I discounted timing, in that nothing has changed on the motor, other than it just stopped working, and the distributor cap is nice and tight, no movement.

Thanks

Ed

 

[PlayDate]

Ed,

The original pumps were mechanical and part of the raw water pump. Somebody could have put an electric fuel pump on it which could be the sound....but that is really loud.

 

[PlayDate]

Well.....it sounds like it has compression and wants to start. I would definitely check timing just to be sure. Easy way is to put a timing light on the other engine and see what it says. I think it is 8 degrees before TDC but the working engine is a good source. Also, double check the firing order since it looks like you have a new cap and wires. One off.....would cause that problem as well.

 

[Ed Whitlock]

Ed,

The original pumps were mechanical and part of the raw water pump. Somebody could have put an electric fuel pump on it which could be the sound....but that is really loud.

Yes, that is what I thought. When I bought the boat, I had an issue starting the stbd engine, and had to empty and refill the fuel filter by turning the engine over several times. That made me think mechanical pump. So I do not think I have a problem in the fuel supply area.

The buzzing is weird and new, and not sure what it is. Just really wish I could get this engine to fire.

Ed

 

[Ed Whitlock]

Well.....it sounds like it has compression and wants to start. I would definitely check timing just to be sure. Easy way is to put a timing light on the other engine and see what it says. I think it is 8 degrees before TDC but the working engine is a good source. Also, double check the firing order since it looks like you have a new cap and wires. One off.....would cause that problem as well.

Duh! thanks for reminding me of the fact that I have a perfectly running identical engine to check the timing. I totally spaced that. I even thought of swapping carbs at one point, but felt it was safer to just rebuild the one, than ruin both.

I will check the timing on the other one tomorrow and see how it compares to the one that won't start.

Ed

 

[PlayDate]

 

[JimG]

Don't forget to compare the plug wires for firing order also...

 

[fc3]

Sounds like fuel starvation to me. Are you sure you setup the carburetor's idle circuits correctly? Try pumping the throttle a bit more to see it she fires.

 

[Ed Whitlock]

Sounds like fuel starvation to me. Are you sure you setup the carburetor's idle circuits correctly? Try pumping the throttle a bit more to see it she fires.

I left the throttle linkage off, as seen in the video, and tried pumping the throttle several times. No matter how many times I pumped the throttle, it would not start. It sounded like it wanted to many times.

The only time that I got it to start was once when I left eh throttle wide open, and it finally started, and then died when I lowered the throttle back to idle. It has not started again since, even with the throttle wide open.

I left the throttle wide open this last time after rebuilding the carb, knowing that the idle screw may not be set properly. I was going to set it once I got it started so that it runs well.

I also sprayed starting fluid into the carb intake, to see if that made a difference, but no start.

Ed

 

[Ed Whitlock]

Don't forget to compare the plug wires for firing order also...

Thank you for the back up. I made sure to mark the wires, there are tags on the cables, to make sure that they were in the right place.

 

[erikth]

I would grab a can of starting fluid (in Canada we have something called Motomaster Quick start) that is basically a highly flammable spray. Spray it into the carb as you try to start it. If that works, then it might be a fuel supply issue. If that does not help, then a fuel issue is less likely. It's a very cheap test and it might even get you going.

 

[Ed Whitlock]

I would grab a can of starting fluid (in Canada we have something called Motomaster Quick start) that is basically a highly flammable spray. Spray it into the carb as you try to start it. If that works, then it might be a fuel supply issue. If that does not help, then a fuel issue is less likely. It's a very cheap test and it might even get you going.

That was the last thing that i tried. No joy on the starting fluid, either.

Thanks

Ed

 

[CliffA]

you said you verified you have spark at the distributor cap....did you verify you have spark at the spark plugs?...are you sure the plugs are gapped properly?...

cliff

 

[Ed Whitlock]

you said you verified you have spark at the distributor cap....did you verify you have spark at the spark plugs?...are you sure the plugs are gapped properly?...

cliff

I used the timing light to verify spark was leaving the cap on each wire, but did not check the end of each wire, since they are less than 6 months old. The engine was running fine before it just started to cut out at low idle, and now won't start. The plugs in 1, 3, and 5 are new, since I could reach those, and they were gapped correctly, and the engine actually fired once with those wires and plugs installed. It just only ran while at full throttle, and cut out at low rpm. So, i think those are okay, but I can always go back in and check.

Thanks

Ed