HELP! Engine Won't Start - Looking For Ideas

O

Old Vet

New Member
Sep 12, 2010
706
St Lawrence River/1000 Islands
Boat Info
1987 268 Sundancer
Engines
454 Magnum, Alpha One
So.....I gotta be the luckiest S.O.B. around here......I guess.

Nice slow leisurely 2 hour ride home yesterday......putting along at 1600 RPM. Everything felt and sounded great.....all gauges normal....no issues at all.

UNTIL.......I got right to the end of my dock....start jockeying around to back 'er in.......and the old girl just stalled. Folks on the dock pulled me in.

Wouldn't restart.....cranked over great.....no start.

So today......a mechanic happened to be around. I replaced the distributor cap and rotor and plugs.

Lots of fuel....he checked for spark. Good spark off the coil. Spark at the end of the plug wires...at the plug.

But it won't fire. Oddest thing is after cranking it.....it kind of "diesels"......chugs for a second or two and puffs some good smoke back out the flame arrestor.

So now I'm stuck as to where to look next.

Open to all ideas please guys. Thanks.
 
Ok, he replace the cap rotor and plugs. How about the pickups? Timing? Does it have a Thunderbolt ICM? You say it's getting spark, is it good and strong?
 
If you have spark at the plugs you likey have an ignition timing problem or a fuel supply problem....you mentioned you have plenty of fuel in the tank but is it making its way to the carb?....you can disconnect the fuel supply line at the carb and hold the end in a bucket while you crank the engine to verify the fuel is getting pumped to the carb....if you are getting fuel being pumped you could have a problem with the carb (check the inline fuel filter screen at the carb if you have one) or a timing issue....if no fuel is being pumped check the fuel system components one at a time to find out why....

cliff
 
Yup.....wondered about timing. Was just so odd......was sitting still at idle basically when it just stalled. Wouldn't refire. Timing chain jumping seems odd under those conditions....but don't know. More checking tomorrow.

Mechanic talked about the "pick up" today. Said we could try changing that on Weds if the rotor, cap and plugs don't do it. Just not crazy about simply changing parts until we stumble across the "right one",,,,,but......seems the way many troubleshoot these days.

Yes....I have a Thunderbolt IV breakerless ignition module.

"You say it's getting spark, is it good and strong?"

Mechanic seemed satisfied with the strength of the spark.

"you mentioned you have plenty of fuel in the tank but is it making its way to the carb?"

I had the flame arrestor off and a buddy looked in the carb as I pumped the throttle and he said he saw fuel shooting in.

However......with all the cranking I did....I would have expected to smell more gas....as though it was flooding itself....but I didn't really smell much in the way of gas.

When I pulled the old plugs....they didn't really look very wet....could smell a little gas on them....but they weren't really wet as though I was getting an abundance of gas into the cylinders flooding it.

Will look at the filter at the carb tomorrow as well.

Don't really know how to describe it but....rather odd kind of "chug-chug" stutter when I stop cranking it and then the puff of smoke out the flame arrestor. Almost like it's doing a little "reverse rotation" for just a second or two.

Thanks guys.....please keep all thoughts coming.
 
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will the engine start after it has sat for a day or so?....if so there may be a problem with the carb loading up with gas a slow to idle speeds causing the carb to flood out.....once the carb is flooded it can be very difficult to get the engine started....the excess gas in the carb has to have time to evaporate out before running normal again....the fix is to rebuild the carb.....

cliff
 
I had the same problem last week went to start engine it almost sounded like it was starting but wouldn't run looked at everything all good, for some reason I checked the emergency off switch it looked like it was in the on position but had been bumped down just enough to be shorting on-off moved it back to on fired right up.
You might want to try some starting fluid to see if it'll fire at least it will tell you if you have good spark.
Good Luck
 
Pulled the fuel line at the carb today....cranked it a couple times and had lots of fuel shooting out.....so fuel pump is sending it to the carb.

I hoped I'd find a plugged filter at the carb but nope....clean.

"will the engine start after it has sat for a day or so?."

Tried to start it.....no go.

No "chugging" after cranking today.....but when I stopped cranking.....get a bit of a puff of smoke out the flame arrestor. Didn't try it as many times today as yesterday.....didn't seem to be much point.

Couldn't go any farther today......national holiday here....no one to talk to. Back at it tomorrow.
 
Changed the cap and rotor.

BUT.......when putting the wires on the new cap.......was sure to do ONE WIRE AT A TIME! :smt001

A lesson learned many years ago.:grin:
 
if you have adequate strength fire at the plugs and fuel getting to the plugs about the only thing missing is proper ignition timing.....i know your mechanic said he liked the spark he saw at the plugs, but be sure it is a strong, bright blue color spark...if it is a thin, weak, yellow spark it is not hot enough to fire the engine.....ignition coils are relatively cheap so if you have any question at all about the intensity of the spark you may want to install a new coil.....i hate to just throw money at problems like this myself but sometimes that is the best way to go if the answer is not obvious....

cliff
 
After all you have reported so far I would not just throw parts at it until I did a compression test. The old girl may have finally said I can't do this any more. Between rings and especially the valves she may need some mechanical help. Timing chain jump can be picked up in a compression test as well.

You are having back flow through the carb. This is your biggest clue at this moment as you have been checking everything else. Back flow through the carb means compression is getting past one or more intake valves.
 
Gary Hill said:
After all you have reported so far I would not just throw parts at it until I did a compression test. The old girl may have finally said I can't do this any more. Between rings and especially the valves she may need some mechanical help. Timing chain jump can be picked up in a compression test as well.

You are having back flow through the carb. This is your biggest clue at this moment as you have been checking everything else. Back flow through the carb means compression is getting past one or more intake valves.
Click to expand...

very good point Gary.....fuel, spark, timing and compression are all needed to make an engine run.....it is quite possible the missing ingredient here is compression instead of timing.....

cliff
 
Mechanic convinced me today to change the pick up in the distributor...another $89.50 part that did nothing. Oh well. But at least another thing eliminated I guess.

However.....I did get it to start this morning....with the recommendation of a different mechanic.

I loosened the distributor and turned it counter clockwise...perhaps 10-15 degrees or so.

Cranked it and she fired up....ran rough...but i had it running.

According to the second mechanic....if that happens...the signs are pointing to the timing chain jumping.....since I've eliminated pretty much everything else......except a compression test

That's where I left it this morning.

I may very well check compression tomorrow though. I do have a compression gauge here.

If compression checks OK next parts I'll be buying is a timing kit I guess.

Thanks guys.
 
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Old Vet said:
Mechanic convinced me today to change the pick up in the distributor...another $89.50 part that did nothing. Oh well. But at least another thing eliminated I guess.

However.....I did get it to start this morning....with the recommendation of a different mechanic.

I loosened the distributor and turned it counter clockwise...perhaps 10-15 degrees or so.

Cranked it and she fired up....ran rough...but i had it running.

According to the second mechanic....if that happens...the signs are pointing to the timing chain jumping.....since I've eliminated pretty much everything else......except a compression test

That's where I left it this morning.



I may very well check compression tomorrow though. I do have a compression gauge here.

If compression checks OK next parts I'll be buying is a timing kit I guess.

Thanks guys.
Click to expand...




Or you put the wires on 1 post off. It happens, it has to me. even doing one wire at a time
 
I agree with Mike. It would be cheaper to double check the wires than to buy a timing kit. I know I've done this before on an old Ford I had...my dad laughed then chewed my ass, then showed me what I had done

But you did say it was running great then this started correct?
 
Pull your distributor first and inspect the roll pin on the cam gear. If it almost gone,it would behave as you are describing.
Besides, it doesn't cost anything to check.
 
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