Starts when cold, won't when warm.

[elpaso]

What type ignition - Thunderbolt IV - V - ? <br />Year of boat should answer question.

 

[Safari]

Starts when cold, won't when warm.

Yesterday I decided to do a little fishing. Went out to the boat and fired it up.(The engine is a 350 G.M.Mercruiser) True to it’s past behavior, it started within two cranks of the starter. Motored around for a while and found a “fishey” looking place. We drifted for a while, caught a couple of fish, then the bite slacked off and we elected to move on. Turned on the key, crank—crank—crank—crank, motors not starting!! Drifting towards the rocks.!!. Gota get her started. We tried a few more times. I have plenty of gas but don’t want to keep cranking and eventually run the batteries down so we stop to check for spark at a plug. With the plug wire off and cranking, the motor fires up. My buddy puts the plug wire on and we button up and head for shore.<br /><br />What seemed to happen was when the engine had been running and warmed up to 170, the starter spun slower and the batteries seemed to lose their power. I got the boat home and had to get it started to run fresh water through it to flush it. An hour or so had passed so the engine was now somewhat cool. When I hit the key it started right up. I am perplexed as to what might have happened to cause this. It appears as though the problem occurred when the engine was warm, then corrected itself when the engine cooled down. All I know for sure is that I no longer trust the boat.<br /><br />Has anyone had this problem and if so, how did you fix it? --------Thank you

 

[novicetech]

Re: Starts when cold, won't when warm.

Did you check your oil? Make any sudden stops? Some times leaking manifold will leave water in cylinder making motor hard or impossible to turn over.

 

[tommays]

Re: Starts when cold, won't when warm.

you need to be sure what the problem is to find a fix<br /><br />in a safer place when it wont start you need to sure that you are loseing spark or is it a fuel issue<br /><br />once your sure you can start to track down the cause bad connection ,bad coil when hot ect<br /><br />a brand new boat can have the same problem <br /><br />tommays

 

[Safari]

Re: Starts when cold, won't when warm.

Hi novicetech, thanks for the responce. No sudden stops, checked oil befor I left and it was full.

 

[Safari]

Re: Starts when cold, won't when warm.

Hi tommays;<br /><br />When you say losing spark, do you mean at times I might get no spark? Or,do you mean I might be getting a weak spark? How would I test for a weak spark? Where should I check, the plug or the coil?

 

[Olds Eddie]

Re: Starts when cold, won't when warm.

Tommays has it right. Whenever an engine won't start, pull a plug wire and put a phillips screwdriver into boot and hold the shank close to a ground while someone turns the key. If no spark is present you have an ignition problem. If you have a spark, pull the flame arrestor and look down the carb while someone works the throttle. If fuel is present you will see gas squirt from the accelerator pump circuit. Once you have determined the cause of the no start condition you can address the problem. If its the ignition I would replace the coil as thats how they act when they go south.

 

[Jilly - 5]

Re: Starts when cold, won't when warm.

Hot engines always start harder than cold engines. I suspect you've also got a spark timing problem (too retarded). When cold, spark is typically advanced due to all cold ignition components. You're also getting a cold air/fuel mixture into the engine's cold chambers. Cold charge in cold chambers makes the job easy for the starting motor (pushing up pistons on compression stroke) and advanced spark fires nicely after piston makes it over the top. When hot, cold air/fuel charge hits hot cylinders, expands and has staring motor pushing a piston up against an expanded air/fuel charge. Also, spark fires off before piston goes over the top, trying to force piston back to where it came from. This combination of pre-ignition and and tough charge to compress puts terrific load on the starting motor, making you think the batteries are low. They're not. They're just fighting a hell of a load inside the chambers. Try advancing the spark a little (several degrees) to get the spark lighting after the piston passes dead zero (over the top).

 

[cc lancer]

Re: Starts when cold, won't when warm.

On April 24,05, you were testing 11.9 at the starter, low but it will works when cold, but when the engine is hot the starter has to over come the friction in the engine.<br /><br />The starter bushing may be old and worn, if so the starter would drag trying to crank a hot engine.<br />I agree with Tommays, a good tune up may solve the problem.

 

[tommays]

Re: Starts when cold, won't when warm.

Safari<br /><br />after you got that old drive running this should be much less of a problem to find<br /><br />everything is pretty much a guess until you sure of fuel or spark<br /><br />i thing i would start with the basics which would be that it had a recent tune up meaning your cap,rotar,points,condenser and plugs are all good and SET to the correct specs<br /><br />an extra sparkplug is good for seeing if you still have spark i usally check at the easy plug wire to get to <br /><br /><br />some carbs are good at loseing the fuel an can take a lot of cranking to refill??<br /><br />tommays

 

[Safari]

Re: Starts when cold, won't when warm.

Hey tommays, you remember about my old drive-- . You and a few others helped me to get it running again and I can't thank you guys enough. When I first bought that old boat,befor I even launched it, I changed the oil, put in new spark plugs, plug wires, cap and installed an electronic ignition. I had a mechanic do the later. I don't know if he set the timing or not though. Thats a great idea of having an extra spark plug onboard, I'll do that. All I know is that when it is running It doesn't miss a beat------just goes and sounds very stong. This is a brand new problem.<br /><br />Jilly-5 Has described pretty closely what I experienced on the water. That is to say it seemed as though my batteries were low when it shouldn't have been. Maybe if I advance the spark a little it will help the problem. I'm not a mechanic and don't know .

 

[Safari]

Re: Starts when cold, won't when warm.

Thank you cc lancer. (Man-O- Man), I can't believe you guys' memories!! Your right, that was what my multimeter read. But, isn't that volts? Should I be interested in how many Amps the starter is drawing? If so, will my multimeter read this or do I need you buy some other tool?

 

[tommays]

Re: Starts when cold, won't when warm.

if you search here recently there has been a LOT of problems due to bad battery cables and connections<br /><br /><br />if you still down at 11.9 volts as CC says thats low a good battery will hold at least 12.4 volts <br /><br />it doesent sound like much but its a world of diference when cranking time comes<br /><br />tommays

 

[Safari]

Re: Starts when cold, won't when warm.

O.K. I'll pull the batteries and have someone check them.

 

[fendersfender]

Re: Starts when cold, won't when warm.

well........in my humble opinion, I would say that timing is to far advaced, if anything, a warm motor will turn-over hard if timing is too far advanced. I would check timing first and go from there.