Your message covers a lot of different questions....
If your top speed under power is only 4 kts, you need to first eliminate some potential problem areas in the drive train. If you did indeed just buy the boat, then you know that the prop and shaft are clean, and the engine surveyed out OK. You did get a survey. Right?
If so, then look at the pitch on the fixed prop. If engine winds up to max rpm and you are going too slow, then prop is likely quite a bit under-pitched. Seems to me that your boat should do 6 kts easily under power with a clean bottom.
If, OTOH, you want an excuse to install a feathering prop, whether Max or one of its worthy competitors, you would not worry about pitch...
You set the pitch yourself on the feathering props (external adjust. on the Martec, internal and skill-intensive on the smaller Maxprop hub).
Do a search on "prop options" on this site to find a picture of our prop. A search on "prop" will bring up a lot of related Q&A.
Since oodles of older Ericsons (and most other makes of sailboats) have A4's, lots of folks on this site can comment about the "care and feeding" of those engines... And also tell you what prop they are happy with.
Sorry to be so vague, but I would approach the problem from the engine end of things, and worry about funding a Maxprop or other feathering prop (at $1K plus) only after checking out everything in front of the prop. After all, the cost of the featherer could be 10% of the price for the whole darned boat...
Best,
Loren
(who did spring for a feathering Martec for his 34 footer, and likes it)
If your top speed under power is only 4 kts, you need to first eliminate some potential problem areas in the drive train. If you did indeed just buy the boat, then you know that the prop and shaft are clean, and the engine surveyed out OK. You did get a survey. Right?
If so, then look at the pitch on the fixed prop. If engine winds up to max rpm and you are going too slow, then prop is likely quite a bit under-pitched. Seems to me that your boat should do 6 kts easily under power with a clean bottom.
If, OTOH, you want an excuse to install a feathering prop, whether Max or one of its worthy competitors, you would not worry about pitch...
You set the pitch yourself on the feathering props (external adjust. on the Martec, internal and skill-intensive on the smaller Maxprop hub).
Do a search on "prop options" on this site to find a picture of our prop. A search on "prop" will bring up a lot of related Q&A.
Since oodles of older Ericsons (and most other makes of sailboats) have A4's, lots of folks on this site can comment about the "care and feeding" of those engines... And also tell you what prop they are happy with.
Sorry to be so vague, but I would approach the problem from the engine end of things, and worry about funding a Maxprop or other feathering prop (at $1K plus) only after checking out everything in front of the prop. After all, the cost of the featherer could be 10% of the price for the whole darned boat...
Best,
Loren
(who did spring for a feathering Martec for his 34 footer, and likes it)
Last edited:
Bill Sanborn
Member III
I had a similar problem on my E29. Engine was smooth and very quiet but no power. Turned out to be a plugged exhaust pipe.
See if you can get max rpms in neutral. If you can't, check the exhaust pipe where it connects to the exahust manifold. Mine was plugged so that there was only a 1/2" hole remaining. If you do take it off and it has never been replaced you will probably have to replace it.
See if you can get max rpms in neutral. If you can't, check the exhaust pipe where it connects to the exahust manifold. Mine was plugged so that there was only a 1/2" hole remaining. If you do take it off and it has never been replaced you will probably have to replace it.
I also have a 71 E29. I bought it last year. The A-4 engine had been rebuilt in 96. I first noticed it had only two speeds stop and go. The engine would not rev.
After checking everything out, I determined the problem was the prop was too large for the boat. I purchased a new one from Indig electronics. (http://www.atomic4.com/propeller.html)
I immediately noticed a huge improvement. I was very happy with results. The engine ran much smoother and quieter and I have a full range of spped. But within an hour of replacing the prop, the head gasket blew. My theory is that the head gasket was already weak and allowing the engine to obtain higher revs was the final straw.
I get an easy 4+ knots at a relatively low engine speed and can speed it up to over 6 knots (at this time I don't remember the max speed). The only issue I have is that I'm experiencing a lot of "prop walk". Whether this is due to the prop, prop shaft alignment or other cause, I don't know yet.
If you need engine parts for the Atomic 4, I've been very happy with Moyer Marine.
Having an E 29 of the same Vintage, I am very interested in learning more about your boat.
Dave
After checking everything out, I determined the problem was the prop was too large for the boat. I purchased a new one from Indig electronics. (http://www.atomic4.com/propeller.html)
I immediately noticed a huge improvement. I was very happy with results. The engine ran much smoother and quieter and I have a full range of spped. But within an hour of replacing the prop, the head gasket blew. My theory is that the head gasket was already weak and allowing the engine to obtain higher revs was the final straw.
I get an easy 4+ knots at a relatively low engine speed and can speed it up to over 6 knots (at this time I don't remember the max speed). The only issue I have is that I'm experiencing a lot of "prop walk". Whether this is due to the prop, prop shaft alignment or other cause, I don't know yet.
If you need engine parts for the Atomic 4, I've been very happy with Moyer Marine.
Having an E 29 of the same Vintage, I am very interested in learning more about your boat.
Dave
Appreciate all the good pointers.
The engine will rev higher in nuetral than it will under power. I don't know exactly what rpm I am running at because it is not equiped with a tachometer, this problem will be corrected very soon.
The lack of revs under power has lead me to believe the prop is oversized. As soon as I get a tach installed I should have a better idea what is happening engine-wize
Thanks again for your input.
The engine will rev higher in nuetral than it will under power. I don't know exactly what rpm I am running at because it is not equiped with a tachometer, this problem will be corrected very soon.
The lack of revs under power has lead me to believe the prop is oversized. As soon as I get a tach installed I should have a better idea what is happening engine-wize
Thanks again for your input.