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Charles
Charles, Marine Mechanic
Category: Boat
Satisfied Customers: 3341
Experience:  US Navy (Ret) Certified Mercury Marine Tech with over a decade of repair experience.
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We'll I hope so I have a 1988 johnson gt200 ran great after sitting over winter,seco

Customer Question

We'll I hope so I have a 1988 johnson gt200 ran great after sitting over winter,second time out it was lacking about 7mph at wot and it started getting worse to the point that the boat would only go 8mph.now it is hard to start and will not move the boat the plugs were soaked,I'm a car technician for 35 years,but boats are new to me ,I checked spark,tdc on cyl 1 to mark on flywheel,I checked all the carbs,no contamination and blew threw all jets,I checked the reed valves thought they may have broken,I ran a alternat fuel to bypass vro pump,new plugs compression was 100 on all cylinders but the eng wouldn't stay cranking long enough taking compression,did it wot all plugs out. Not sure where to go,the condition that day it happened went from minor to major running condition.
Submitted: 1 year ago.
Category: Boat
Expert:  Tan replied 1 year ago.
Hello. My name is***** will be helping you. I'm a little confused by this statement. ",new plugs compression was 100 on all cylinders but the eng wouldn't stay cranking long enough taking compression"How can you have 100 psi on all cylinders but you couldn't crank long enough to get compression? I'm confused about the second part. "wouldn't stay cranking long enough taking compression"
Expert:  Tan replied 1 year ago.
Have you checked for spark on all cylinders with a spark gap tester?
Customer: replied 1 year ago.
When I was cranking eng doing the compression test the starter would kick out so it wouldn't continue to keep cranking,spark test was don't with a spark tester with a 7/16 gap
Expert:  Tan replied 1 year ago.
What does this mean? "spark test was don't with a spark tester with a 7/16 gap" Do you have spark on all cylinders?
Customer: replied 1 year ago.
Yes a7/16 gap,spark on all cylinders
Expert:  Tan replied 1 year ago.
Were any of the spark plug a different color from the others? Were you able to get compression of 90+ psi on all cylinders? Did you try squeezing the primer bulb when the engine was acting up? How were you able to run the engine on an alternate fuel tank by bypassing the VRO pump? The VRO pump is the fuel pump also?
Customer: replied 1 year ago.
All the plugs were wet the same ,then I put new plugs to get a better reading and had the same result,all soaked,I thought it was the vro pump adding to much oil so I pre mixed fuel in another container and removed and plugged oil feed to use the vro as just a fuel pump with 50/1 fuel ratio, and yes all cylinders had 100psi with a known good snap on tool
Expert:  Tan replied 1 year ago.
Ok right now with the engine off squeeze the primer bulb does it get hard or can you continue to pump the bulb?
Customer: replied 1 year ago.
Gets hard
Customer: replied 1 year ago.
That's why I took all the carbs apart to check needle and seats,and air bleed jets
Expert:  Tan replied 1 year ago.
Wet plugs are weak spark or a flooding issue. Will the engine start right now? If yes can you start it and do a drop cylinder test?
Customer: replied 1 year ago.
I'm alone now but earlier I had another person working the throtle to keep it running ,and as I performed a cyl drop test it didn't seem to change the condition at all no matter what cyl I pulled spark from
Expert:  Tan replied 1 year ago.
So when you did the spark test with the spark gap tester all cylinders jumped a 7/16 " gap correct?
Customer: replied 1 year ago.
Yes they all did
Expert:  Tan replied 1 year ago.
I'm going to opt out and let someone else take this on. I just can't spend anymore time on a question for 11 dollars sorry.
Customer: replied 1 year ago.
My bad I thought that was the whole idea of this sight,thanks
Expert:  Charles replied 1 year ago.
Hello, my name is***** you for allowing me to assist you today.

From all of the testing that you have done and reading what the engine was doing it either got hot and you need to replace the water pump, or the battery was running low on voltage. Test the voltage at the battery with the engine off, then start the engine, rev it to 1500 RPM. Test the voltage right on the battery and at the starter solenoid. they should be with in a few points on the meter with in each other, If the voltage does not come up, most likely you have a failed regulator.

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