Repower Questions

bigirishk · #1 07-28-2003, 09:34 PM

Guys,

What would my '83 V-20 be able to handle on the rear? 200hp max, 225hp? Also, are some dual engines counter-rotating? What does this really mean (not much of a mariner).

I assume I need 25" shaft length. Would all of these big outboards simply bolt right up to my boat, or are there multiple types of mounts and control hookups?

Thanks in advance.

K

macojoe · #2 07-29-2003, 12:15 AM

a 150 hp is all you really need for a V20. I have a 175 and it screams!! As for the motor mounting any motor will mout on the back, but controls will be specfic to the motor brand and year.

chumbucket · #3 07-29-2003, 01:20 AM

Well, if I'm not mistaken, the V20 will handle up to a maximum of 235 HP. Yes, you need a 25" shaft length. There are some motors that are made as counter rotating. This is a term that is used with dual engine setups where the two motors will be turning in opposite directions at the prop. This gives the operator greater control of the steering torque and handling of the boat. Counter rotating engines didn't really come around strong until the late '80's-early '90's when big twin engine outboards became popular. Generally, if someone is selling a single engine, you can bet that it is of standard rotation. Counter rotating engines are usually sold in pairs and advertised that way.
Getting back to the HP question. Do you need 235 HP? no. Might be a lot of fun, but it would be very thirsty on the fuel consumption. On the low end, I wouldn't go much less than a 130 - 140 HP. My buddy's V20 has a 115 Merc and it feels very much under powered to me. I've got a V20 Center Console and run a Yamaha 150 on it and I'm very pleased with the performance as well as fuel consumption. I don't have any real hard numbers yet for the consumption, but can tell you that with the 150 I max out at around 38mph and typically run at 25 - 30 mph cruise speed. At cruise speed it seems to be very efficient.
There are things you can do to help the lower power situation as well such as trim tabs, shifting weight in the boat, reducing weight, etc. Hope this helps.

bigirishk · #4 07-29-2003, 02:24 PM

Does the counter-rotating engine actually spin the opposite direction, or is it a function of the lower unit?

labii · #5 07-29-2003, 05:15 PM

As far as I know it is the lower unit .

labii · #6 07-29-2003, 05:37 PM

I have a friend who just replaced a 200 merc on his V20 Fisherman with a 225 optimax . He liked the boat much better with the 200 . The boat was even faster . The 200 was turning up 5700rpm vs 5300rpm for the optimax . He got about 53mph out of the 200 and 48mph out of the 225. They are proped differently . The big thing is the weight . The optmax is so heavy that water does not drain out of one side of the boat at the dock. He is going to move his battery from that side to the center console . His boat is a 1986 and is rated for 235hp . Mine is a 1994 and rated for 200hp at the prop . I think that the specs. are listed under the 1994 . catalog on the home page. He did say that his fuel consumption is way down with the opti .

chumbucket · #7 07-29-2003, 11:49 PM

That surprises me because the Optimax is fuel injected. You would think it would be more economical to run.

labii · #8 07-30-2003, 11:19 AM

It is much better . He says about 1/3 less consumption.

#9 07-30-2003, 06:15 PM

For what it's worth, my 87 V20 has a 20" transom.

Lance

bigshrimpin · #10 07-31-2003, 12:16 PM

Lance . . . can you post pics. I've seen an 86' with a 20" transom. I just assumed that it was modified.