grew153owner
Cadet
- Joined
- Dec 15, 2008
- Messages
- 15
I have a 1967 thunderbolt 500. It starts first turn of the key and idles fine in neutral. Under load it does not perform well.....10-15 miles per hour at wot on a 15 ft Grew. At lower speeds at the marina it also stalls. When I remove the plugs (brand new) I don't see much evidence of use on cylinder 1, 2 other cylinders shows use and another cylinder was particulary dirty. I bought this boat 1 year ago and it has only ran for about 1 hour since I bought it, it's probable it sat for a few years before then. I took it to a marine mechanic for a tune up last fall and he adjusted floats etc. but only ran it on the trailer at the ramp and not in the water. When I bought the boat I put a newer fuel tank and put new fuel in it.
I am concerned about cylinder number 1 but do not know how to check for spark with these gapless plugs. Compression is 125 in cylinder 1 and 130 in 2-4. i hope to get it on the water this weekend and try to run for an hour to see if that helps. At the recommendation of the marine mechanic I also put carb cleaner in the gas.
Anything else I can try.
I am concerned about cylinder number 1 but do not know how to check for spark with these gapless plugs. Compression is 125 in cylinder 1 and 130 in 2-4. i hope to get it on the water this weekend and try to run for an hour to see if that helps. At the recommendation of the marine mechanic I also put carb cleaner in the gas.
Anything else I can try.