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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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Jeff, I have just bought a project 91 Glasstream I/O mercruiser

Customer Question

I have just bought a project 91 Glasstream I/O mercruiser 4.3/V6 w/ Thunderbolt IV ignition . The boat has sat for quiet some years due to previous owner not repairing the original problem of shutting off when put in gear . We removed the safety switch and was able to crank the engine , unbelievably it idled as well as throttled up quite well in the yard with the waterhose connected to foot . We had used a portable fuel tank for testing and upon the first run it did ok until returning to dock ,where it died but continued to allow fuel to fill the carb. We bought and installed carb kit and upon changing the oil discovered a fair amount of fuel in the oil. After rebuild of carb and fresh oil we attempted a second test, ran great on land with water hose connected, this time it started out gould but would not plane off and when we checked oil , contained gas again . Round three, we removed factory fuel pump , blocked off where mounted to block, installed a electric
pump w/regulator , changed oil and filter . Runs great on hose at house, took to water for test and same thing , breaks down and wont plane off, checked the oil and again there is gas in it.
In my research on the Thunderbolt IVignition , i believe the breaking down is due to the ignition module on the distributer , but the fuel in the oil has me confused. Sorry for so much info in getting to what help l am needing but just wanted you to know Everything.
James in Ala
Submitted: 2 years ago.
Category: Boat
Expert:  Tan replied 2 years ago.
Hello. My name is***** will be assisting you. The fuel in the oil is from the carburetor flooding. Did you change the oil after rebuilding the carburetor? On the fuel pump how do you control the fuel pump? Is it connected to a oil pressure switch? As for the ignition this could be something as easy as a failing ignition coil. Do you have a timing light to water the spark when the engine starts to act up?

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