mike7a10
04-03-2005, 08:33 AM
I am probably the newest A-4 owner on this site and am very happy to have found it! I just purchased a 1975 32.5 Irwin center cockpit sailboat. The A-4 starts up great and purrs along under around 1800 rpm.
At 1800 rpm I am going about 4 knots. The hull speed is about 6 knots. The bottom and prop were just cleaned and got good marks from the professional who cleaned it. It made a huge difference as it would only top out at about 2 knots during the sea trial.
Once I go above 2000 rpm, the boat tops out at about 4.1 or so knots and then the prop appears to cavitate and the engine revs up to about 4000 rpm or so and I quickly lower the rpm and the prop seems to re-engage and we chug along.
Also the operating temp at 1500 rpm is around 150 degrees and when I push it to around 2000 rpm it goes to about 180 degrees. Is that a normal operating temp for the A-4.
I have read about the Indigo prop for the A-4 and am wondering whether this would be a good move? I am also contemplating changing out the spark plugs as they appear to be rusty and I have no idea how old they are. I am also going to run a compression check ASAP just to see.
Luckily the guy I bought the boat from has the Moyer manual so I have a small amount of knowledge (which is of course dangerous!) about the A-4 and look forward to learning more.
At 1800 rpm I am going about 4 knots. The hull speed is about 6 knots. The bottom and prop were just cleaned and got good marks from the professional who cleaned it. It made a huge difference as it would only top out at about 2 knots during the sea trial.
Once I go above 2000 rpm, the boat tops out at about 4.1 or so knots and then the prop appears to cavitate and the engine revs up to about 4000 rpm or so and I quickly lower the rpm and the prop seems to re-engage and we chug along.
Also the operating temp at 1500 rpm is around 150 degrees and when I push it to around 2000 rpm it goes to about 180 degrees. Is that a normal operating temp for the A-4.
I have read about the Indigo prop for the A-4 and am wondering whether this would be a good move? I am also contemplating changing out the spark plugs as they appear to be rusty and I have no idea how old they are. I am also going to run a compression check ASAP just to see.
Luckily the guy I bought the boat from has the Moyer manual so I have a small amount of knowledge (which is of course dangerous!) about the A-4 and look forward to learning more.