I recently bought a 1993 Larson with the 3.0L mercrusier. The guy I bought it from was a good friend. He recently had it running with muffs a month ago and in the water running and driving it around the lake with multiple on/offs within the same trip a couple weekends ago. Last weekend he tried to get it started on the lake but it would not start. He said it would turn over but it would not fire? What could be the issue? Spark? Thanks.
An engine needs fuel, spark, compression - and all three coming together at the correct time. Diagnosing is easy. Check for spark, check for fuel, and check for compression. If you have those three, then timing is off.
1. check for spark by seeing if the spark plugs spark if they are removed and grounded - this is best done when the spark plug is not in bright sunlight.
2. check for fuel by seeing if it starts with starting fluid squirted into the carb. If it starts, your need to find the cause of the fuel blockage or clean the filters or perhaps clean the carb. A leak in the pick up so that you are sucking air instead of fuel is also a possibility.
3. check for compression with a compression pressure gauge. Should all be above 130 or so and all values within 10 percent of each other.
4. check for timing with a timing light
