Seems the motor will crank strong and run when on muffs. When he gets out and motor is in lake, motor struggles to crank and will not start. Has tried new battery but same results. Battery had been moved to front of boat with extended cable. He is in the process of relocating to the back of the boat. With that said, not sure why it will crank strong out of water, but weak when motor is in water. Any thoughts appreciated.
Pull Out The Spark plugs and crank it in the water (Is water coming out where it is not suppose to? Had a motor problem that sounded like this but not even close to the same age and it was a merc.
As far as other advise on a 1972 ASK THE OLD TIMERS here.
If its older than 10 I start to hummmm so I can't here you talking.
If Its older than 20 I start to hummmm, close my eyes, and break out the torch.
After that I call the scrap man for a proper barial.
or brake out the brown box.
(New Jersey SALT water)
I would quess at least one cylinder is not up to specs. First a compression test, blown/leaking cyliner head gasket?, A spark test to look at strength of all three, bad coil(s)?, amplifier?. All that being average, with engine running at idle, remove each spark plug wire separately to see if engine dies or continues to run. The wire that comes off and makes no difference, look to the carb for a plugged slow speed jet and the need to clean and put a kit in all the carbs. Then there are the less common problems such as reed tip broken off, etc.........If you don't have a compression gauge, timeing light, tools and a manual.. Take it to someone who does.
Backfire
Bingo. Pulled plug wires one at a time. Only the plug on top cylinder made any difference, as in motor quit running. So just to confirm, this would mean motor is running on one cylinder?. Spark on all three plugs are good as well as compression. So it is leaning toward a fuel issue. He will check carbs next.
you also need to remember that on muffs there is no back pressure on the exhust and a lot of times a motor will run good on then but losy in a test tank or on the lake. that is why a test tank or a lake test is what is needed to properly repair a motor, and do carb adjustments.
[I]TEAM CORGI DOG[I]
1996 javelin 400T /1996 Johnson 200 Venom
clean those carbs and i bet your problem will go away.
2022 Hog Island Skiff
Johnson 70/40 jet
1992 Champion 184
1992 Evinrude Intruder 150 hp
Bouncin' off rocks, and catching the smallies.
Potomac River Smallmouth Guide
Owner of Potomac Custom Tackle
Compression good. New spark plugs. Carbs rebuilt. He took it out the other day and fired right up. Could get to full rpm range using the fast idle out of gear. When he is in gear, boat would only push at low speed and said he could get to 3500 rpm. Thought it might be the prop slipping but he said the rpm's would steadily drop. Anyone have any thoughts to help get us in the right direction?
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