RESOLVED: Hard start/no start when warm

[muskyfins]

Getting a late start to my boating season this year. Boat was winterized (fall) and summerized (2 weeks ago) per the adults only thread here on iboats. No problems at summerization, but yesterday, I started her on muffs in driveway. When cold, she started up with zero issues. Got up to temp. Purrs like a kitten. Shut off for maybe 30 seconds and attempted restart and cranks but no start. Sounds flooded, smells flooded, but neither full or part throttle would get her running. After sitting for an hour or so, went back out and she started up like brand new. I have repeated the process for about 10 hours yesterday trying to determine the cause with exactly repeatable results. The only way she'll start warm is if I immediately retart (less than 5 seconds) or if I give her a shot of ether. (I know...major no-no) When she runs whether warm or cold, she runs like brand new, it's just this starting issue. Any help is appreciated- I already missed half the season, and now left my family disappointed on another missed day on the lake.

1993 Stingray 606
Mercruiser 188 (not original to boat)
Holley 2 barrel

PS- I have looked into carb throat to see if fuel was leaking down (stuck float) and didn't see any. Choke was functioning correctly.

 

[hivoltg]

Re: Hard start/no start when warm

Re: Hard start/no start when warm

Was anything changed out or rerouted during the winter?

Maybe your fuel line is getting hot enough to cause an issue (vapor lock).

 

[muskyfins]

Re: Hard start/no start when warm

Re: Hard start/no start when warm

I thought about vapor lock, but my engine hatch was wide open. I mean wide open-fully exposed engine.
Nothing changed location or position.

 

[hivoltg]

Re: Hard start/no start when warm

Re: Hard start/no start when warm

I would test the ignition side of it then (spark plugs, coil, distributor, ect).

If you have a timing light: check the timing when its cold and then again when its warmed up. I wonder if your timings going erratic like a bad coil or the initial timing is too advanced.

When it wont start if you can safely check what color the spark is off a plug see if it looks yellow instead of blue like a weak coil would do. An ohm meter off the coil is probably a safer method.

I would also check all your battery grounds off the motor and clean them. This can also make a coil seem weak.

 

[slothman]

Re: Hard start/no start when warm

Re: Hard start/no start when warm

maybe the coil is heating up and not creating enough spark? Maybe pull the wire from the coil and see how much spark you are getting. I'm having the same type of problem. And my coil looks really crappy inside lol.

 

[alldodge]

Re: Hard start/no start when warm

Re: Hard start/no start when warm

Getting a late start to my boating season this year. Boat was winterized (fall) and summerized (2 weeks ago) per the adults only thread here on iboats. No problems at summerization, but yesterday, I started her on muffs in driveway. When cold, she started up with zero issues. Got up to temp. Purrs like a kitten. Shut off for maybe 30 seconds and attempted restart and cranks but no start. Sounds flooded, smells flooded, but neither full or part throttle would get her running. After sitting for an hour or so, went back out and she started up like brand new. I have repeated the process for about 10 hours yesterday trying to determine the cause with exactly repeatable results. The only way she'll start warm is if I immediately retart (less than 5 seconds) or if I give her a shot of ether. (I know...major no-no) When she runs whether warm or cold, she runs like brand new, it's just this starting issue. Any help is appreciated- I already missed half the season, and now left my family disappointed on another missed day on the lake.

1993 Stingray 606
Mercruiser 188 (not original to boat)
Holley 2 barrel

PS- I have looked into carb throat to see if fuel was leaking down (stuck float) and didn't see any. Choke was functioning correctly.

Check your spark as others mentioned but if your smelling fuel it's probably flooding. Pull a plug or two and see if there wet. Could be the crab body has an issue.

 

[muskyfins]

RESOLVED: Hard start/no start when warm

For lessons learned and a good laugh, start here. For cliffs, skip to bottom of post.

Last year one of my trailer lights wasn't working. Don't remember which and it doesn't matter. My truck is a 2002 I've impeccably maintained and was the Admiral's daily driver (so babied). My son (20 years old) and I replaced bulbs, replaced grounds, replaced wiring, replaced light housings-wich encompassed several hours and countless trips to the auto parts store. The weird thing is that the problem was sort of intermittent. Check for voltage and we had voltage at light, so it must be the light. Right? Anyway, we chased the problem for the better part of an afternoon and were ready to call it off. It was hot and he was leaning on the back of the boat when I disconnected the lights from the truck. "Dad, they're on!!!" he yelled. What?

I had thought several times about the truck, but considering how fanatical I am about maintenance and we use it every weekend to pull something and have never, never had a problem, I thought it isn't the truck. No way its the truck. Guess what, bad ground to receptacle on truck.....

We're a super mechanical family. Me and the kid swapped that engine into that boat in 5 hours and a 12 pack. (Merc 188/5.0 ford). Been working on cars since tuning up my dad's 78 LTD wagon. As we attempted to diagnose this issue, we went through all the usual steps-air, fuel, spark. It started fine if it was restarted immediately after shut down. Tuned up recently-plugs, cap, rotor, points, condensor. We had spark. No fuel leakage into carb.

So the kid says "dad, you know, we never replaced the coil" I replied, "son, the coils on those 302 Fords never go bad" (do you see where this is going yet?) Luckily, I know a pretty good marine mechanic and he didn't hose me. Cost of new coil and $100 to him for the trouble.

I am embarassed that I took the short cut of not checking the voltage at the coil. (which was 4 volts) Run a jumper wire to the coil and she starts up every time. Replaced failing coil and problem is gone.

Thanks to everyone for their suggestions.

PS-it sounded flooded because it was flooded, but not because of carb, but lack of sufficient spark. When engine cooled off overnight, she must have had just enough spark to light up. Ether can fire with weaker spark, which got her going when hot.

 

[muskyfins]

Re: RESOLVED: Hard start/no start when warm

PS-kudos to everyone on here that said coil/spark. We changed everything else and had spark, just not enough. In the bright sun, we couldn't tell that it was weak. Proper diagnosis.......

 

[alldodge]

Re: RESOLVED: Hard start/no start when warm

Glad it worked out and your back boating

Until next time :thumb:

 

[slothman]

Re: RESOLVED: Hard start/no start when warm

PS-kudos to everyone on here that said coil/spark. We changed everything else and had spark, just not enough. In the bright sun, we couldn't tell that it was weak. Proper diagnosis.......

lol yep I'm in the same boat. new coil is in the mail. $38 is worth the insurance for sure.

 

[hivoltg]

Re: RESOLVED: Hard start/no start when warm

Good to hear muskyfins. Happy boating.

 

[Mr_Mike_2]

So, I'm in the same boat (ok, similar.. '89 OMC 5.8L.. Four Winns if it matters) y'all are - won't start when warm/hot.
But I've replaced the coil, slave-solenoid, battery cables, distributor, cleaned terminals.. even replaced the points with a Pertronix (which works great once it starts). The Slave solenoid sends a bonus 2 V straight to the coil+ terminal while cranking, and I've verified voltage (10.5 while cranking), checked for spark, pulled plugs (dry/clean). Checked fuel (not dripping, carb rebuilt a few yrs back and kept clean). An hour or two later, Vroom and runs well.
Two batteries on Perko switch. I've checked voltage drops all around and lose a total of about 1.3 V. Air, Fuel, Spark... all there... what am I missing??