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New motor wonbt run in the water

C

cliffpaul2

New member
"I bought a GM 305 Long block

"I bought a GM 305 Long block as a long block and have put it together over the course of the last 6 months. A professional mechanic tuned and adjusted it for me last week and I expected it to run perfectly when I took my family for a ride today. I ran it in the street for 45 minutes before we left just to be sure that everything was OK, and before I shut it down, it was running perfectly. 30 minutes later, I launched it in the lake and it wouldn't even spark. It just cranks and cranks. I tried again when I got home and it wouldn't run on the garden hose either, but the batteries were pretty low from all of the earlier cranking. I'll try again in the morning with fresh charged batteries.

Could this be temp related? It didn't overheat when I ran it, according to the guage.

It's a remanufactured motor with a (1980)280 drive. Any ideas? Thanks in advance!"
 
"Cliff, one thing you have to

"Cliff, one thing you have to keep in mind is that the idle speed and idle mixture must be adjusted with the boat in the water, not in the driveway.

I would first remove one of the spark plugs ignition wires, then insert a spare spark plug on it and ground the spark plug to the bock, then attempt to start. If you get spark, then the problem is not ignition related unless the timing has changed (your mechanic may have forgotten to tighten the distributor clamp). If there is no spark, you may want to hotwire the + of the coil with the + of the battery and attempt to start again. If now you get spark, then the problem is ignition switch or wiring. If you still don't get spark, then the problem would be either the igntion coil or the distributor. To test for the ignition coil, repeat the test but instead of using a spark plug wire and a spark plug, remove fromt he middle of the distributor the ignition wire coming from the coil, keep the end 3/8" from the block and try to start again: if there is spark,then the problem is the distributor; and if not, the problem is either the coil or the distributor points or electronic ignition.

If you get spark and you are convinced that he ignition timing is correct, then you may want to remove the fuel line going to the carb, then crank the engine and see if the fuel pump is pumping fuel (maybe someone closed the fuel valve to the tank?).

Well, those would be the basics. If that does not solve the problem, we can dig deper into it."
 
"As I said, the mech could hav

"As I said, the mech could have forgotten to tighten the distributor clamp. Also, when a coil fails, it fails; and same happens to a distributor. And a wire can become loose or break at any time. Finally, it is not uncommon to find some weird problems after a new engine installation."
 
"What fell off on the way to t

"What fell off on the way to the ramp? Did you close a valve or disconnect something? My money is on it being something simple..........
Good luck,
Jon"
 
"I just tried it again on the

"I just tried it again on the garden hose with fresh batteries and I still don't have a spark. I didn't find any wires that might have come undone and the distributor is secured in position (the clamp is still tight). The coil is brand new and is compatible with the distributor, so I can't believe that it would be causing the problem. Fuel is flowing from the tank to the carb. Any other suggestions before I take it back to the mechanic?"
 
"Good news! I used your sugge

"Good news! I used your suggestions and went a step further and solved the problem! The coil and the wire to the center post of the distributor were getting current, but none was getting beyond that, so I opened up the distributor and found a small wire connection that had worked itself loose. Bingo! I'm back in business!

I took the boat out later the same day for a 3 hour, 40 mile run to start the break-in period. Thanks for your help!"
 
"You are welcome. Happy boatin

"You are welcome. Happy boating.
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"
 
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