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Ask Dominick Your Own Question
Dominick, Marine Mechanic
Category: Boat
Satisfied Customers: 1009
Experience:  25 Years Experience as Mechanic, 20 Yrs Boat Yard Owner/Mechanic, Factory Certified
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Hay good morning i have an 80 s johnson 48 spl been running

Customer Question

hay good morning i have an 80 s johnson 48 spl been running great went to start again and it wouldnt start since then i got it to start breifly and it was running ruff
Submitted: 2 years ago.
Category: Boat
Expert:  Tan replied 2 years ago.
Hello. My name is***** need to do a spark and compression test to start off with. The compression must 80+ psi with no more than 15% difference. The spark must jump a 7/16" gap on a spark gap tester. Do these checks and post back with findings.
Customer: replied 2 years ago.
thanks man ill just take it to the shop do you have alot of typical home owners that do theyre own compression test nothing catostrophic happnd for sudden loss of compression and like i said in the question its not always getting spark i know enough to know its in the ignition system sorry to bother you
Expert:  Tan replied 2 years ago.
No bother. The compression test is to determine the health of the engine. The engine is 35 years old so the compression test is necessary. You can rent a compression tester from the auto parts store. As for intermittent spark it can be number of different things. How do you know it's no getting spark are you testing with a spark gap tester. The gap tester is the only way to know the strength of the spark. There is no easy to test to find a problem without testing. I can make educated guesses but verification by testing isd the only real way to know. What exactly were you expecting?

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