Hydrofoil on Merc V8??

[sowenssw]

I'm finally beginning to get my rig dialed in. Been a bit of a challenge. Biggest issue has been getting out of the hole (loaded). I have it acceptable (at least to me) right now, but always looking to try and improve the hole shot. Anyone running a hydrofoil on a Mercury v8?

Full tank of fuel, (2) 190 lb guys on board, (my tournament load), boat gets on plane super good,......fill the live well and it struggles to plane.

I had a foil on my 250 Sport XS (same boat) and it helped it a lot and was wondering if it could do the same for my 250R??

Current set up:
20XDC
250R
1:75 / Sportmaster
14" Bob Hydraulic jack plate
Prop (still experimenting)

[jr 22]

Getting a foil on my XRS/300R is going to happen in the next month or so.

[jaxbass]

Hi John - I remember that you have both lower units, are you putting the foil on your 1.60 or 1.75 gears?

[rocketmanjp]

FWIW, I have heard Merc will void warranty if you have LU trouble & have a foil. I have a SS CB Marine Foil setup to mount with longer anode bolts & with waterproof tape between foil & cav plate so it wont scratch cav plate & can be removed & shouldn’t be able to tell it was there. I didn’t find it helped on my 21SDC. I am willing to sell it if you are interested. PM me.

[Dan21XRS]

The new cavitation plates are supposed to be hollow or honeycombed designed, that's why you'll void the warranty... Post over on the Mercury 4 stroke page for a definitive answer from the experts... Dan

[jr 22]

I am not so concerned about the drilling voiding warranty on something not caused by the drilling of cavitation plate. I am more concerned about a design (shape and position) that gives the same positive results people have seen on the 2.5 and 3.0 litre motors. Since I have purchased a used 1.75 unit, there is no warranty on it and I also have the original 1.60 to experiment with. Like the CB foil mounting John described above it uses the anode mounting bolts. Maybe the foil needs to be larger or shaped differently for the heavy 4 stroke with large SM gear case? Are there guys that have tried foils on 2.5 and 3.0 motors that have had the same experience that it didn't help their boats?
That said I am looking for feedback and advice from those like John Powell (rocketmanjp) who just posted that a SS CB Foil did nothing. Maybe the foil needs redesigned to be effective on the 300R that struggles to get on plane loaded heavy (unless you drop in pitch 3 or 4 steps). I am hesitant to say loaded heavy, you can almost say loaded normal for a fishing boat. I am returning home to Ohio next month from being located out of town 6 months for work. I hope to do some experimenting back home in Ohio. Any feedback will be appreciated.

[rocketmanjp]

I even tried a different design foil (mike ray) that worked best for me on my 300xs & better than the allison style foil and it did not help any more than the cb marine foil. I do now have 2.5 degree wedges which I find do help.

[sowenssw]

Thanks for the info guys. As I mentioned, I was running a foil on my 250 Sport XS, and it seemed to help. I was also running the 2.5 degree wedges, so maybe it was the combination of both of them. I might consider both again. I really don't like running a foil, I've always felt like having to run a foil is a sign something isn't right about the set up (but that just my personal opinion, and prob wrong).

[tlt20xd]

Jr22 give me a pm when your back maybe we can talk a minute. I've got a 300r on a SST. Terrible results and very disappointing to this point with multiple props.

[jaxbass]

Tlt20xd what gears are you running and having trouble with?

[tlt20xd]

1.75:1 on a sport master.

[Elwood]

I even tried a different design foil (mike ray) that worked best for me on my 300xs & better than the allison style foil and it did not help any more than the cb marine foil. I do now have 2.5 degree wedges which I find do help.

I would like to hear more about the wedges and how much they helped.....

[rocketmanjp]

I didnt do any timed testing it just seems to plane faster & with less bow rise with the wedges.