Willard 730

Stringer Bell · 11 November 2022, 23:17

Hey guys, need some help with 02 Willard. Its setup with Cummins 6BT 5.9 non-aftercooled (210hp) and Mercruiser Bravo 2X Diesel drive. I am running 19.3" x 15p Solas aluminum prop. I can get 2800rpm or so light (2600rpm rated loaded), but speed is limited to low 20s cruise and mid 20s WOT. What are others seeing with same power combo? Konrad drives seem to be able to get mid 30s with single prop, on same 210hp 6BT. Must be the gearing....

Also looking for info on increasing the fuel tank capacity from 35gal to 70gal, was told there is enough space and it would fit in the same compartment in front of the motor? Anyone done it before?

Anyone selling Willard parts? Looking for tiller handle for Mercruiser drive, and for leaning post frame. Tnx

upload pic

SoCal Hurricane · 13 November 2022, 04:14

Confirm your prop size again please.

I run a zodiac 733 with the same setup (210 6BT w/bravo 2). At WOT my rpm is 2600 (give or take a smidgen) and in 2-3 @ 10+ I can consistently hit 45mph (39kts).

If your tach is accurate, and you should calibrate or test it to confirm, you don’t have a gear problem. You have a prop size issue…

Check the prop size and attach a picture of it if able, along with a picture of the stamp on the prop.

Granted, the zodiac 733 hull is slightly different from the Willard. But it ain’t that far off speed wise if propped correctly…

The Konrad drive is fantastic, but if you have a good bravo 2, there is no reason to spend the money unless you’ve got one laying around or light cigars with hundred dollar bills.

SoCal Hurricane · 13 November 2022, 04:38

One last thing… and I’ll verify as well on my end, but I’m pretty sure that my prop is a 17 3/4 x 21P.

I’m also not sure if you can get a 19.3” on that shaft which is why I asked for a pic of the prop on the drive, as well as the stamp.

My best guess is that maybe you’re running a 15” x 19P…?? If that’s the case, then you’ll definitely see higher RPM and significantly lower speed as you stated.

FYI… my prop is stainless and an f’ing tank.

Look up the Solas Titan 1641-175-23 or the 1642-175-23.

I’d stay away from aluminum as well and spend a few extra dollars on a stainless prop.

Bigtalljv · 13 November 2022, 11:47

I put a 65gal fuel tank in the stock position. You might be able to get a few more gallons, I’m gas not diesel. I cut the top off the old tank and use it as the deck, new tank is all below.

Jason

Stringer Bell · 13 November 2022, 19:23

Thanks guys. Prop is brand new Solas Amita 19.3 inch diameter, and 15 pitch. Boat came to me with 18.8 inch diameter and 21 pitch, but i was not seeing the rated rpm when wide open, so i scaled pitch down to get over 2600 rpm wide open. I sold 21p to friend with 454 big block gas motor and Bravo 2. All my props have been aluminum. I also have 17.5 diam 23p aluminum prop without hub, nobody will press the hub in as they claim alu prop will crack from press. These are prop shops so i tend to believe them. I also don't see me getting rpms out of 23p prop, but will try and see what pans out.

Thanks for the fuel tank suggestion, i plan 400nm r/t towing some boats and was gonna try and avoid flex tank on deck or plastic jugs

I also have H733 that is bare hull, getting transom glassed for bracket and 08 Suzuki 300 in next few months.

I will check the tach for accuracy

Stringer Bell · 13 November 2022, 19:38

Solas lists prop up to 19.5 inch for Bravo Two

Stringer Bell · 15 November 2022, 20:04

I opened the upper unit and counted the deive teeth, looks like 1.5 or 1.36:1 ratio (29 teeth on the upper gear). I dont think its 1.81 like standare Bravo 2 has

SoCal Hurricane · 18 November 2022, 06:11

Apologies for the delay here. Been one of those weeks…

My gearing is 1.50:1
My prop is 17 3/4 x 21p

The stats are all in the previous response, but as I said, I can continuously hit the 2600 rpm and top end speed.

Not sure what else I can add here. Hope this is helpful…

Stringer Bell · 18 November 2022, 15:05

Thank you!!!!

I will try to turn the motor and count prop turns to verify the ratio, not sure where to grab the crank to spin it around with a wrench? It doesn't have the single crank bolt. Maybe bump the starter if all else fails....

Thanks for your insight it is much appreciated

Quote:

Originally Posted by SoCal Hurricane

Apologies for the delay here. Been one of those weeks…

My gearing is 1.50:1
My prop is 17 3/4 x 21p

The stats are all in the previous response, but as I said, I can continuously hit the 2600 rpm and top end speed.

Not sure what else I can add here. Hope this is helpful…

SoCal Hurricane · 18 November 2022, 23:41

Is the drive not marked? There is typically a tag attached to the port side of the drive (metal tag, laser engraved, looks like a slim dog tag), or the drive itself is stamped with the gear ratio when they didn’t include the tag.

Stringer Bell · 20 May 2023, 23:23

Been battling some PU Wing tube issues, so havent been able to test other props until last week. Was able to find one used SS PowerTech 17.75x22p, got me 24mph and 2000rpm. Ran out of RPM at 3/4 throttle approx, after that all smoke no gain. Got new SS Solas Titan 17.75x21p, got same 24mph and 2000rpm max. Load was about the same on both prop sea trials. Original aluminum 18.8x21p gave me 2500rpm and 25mph light, that was the fastest I have had the boat to date

Stringer Bell · 22 May 2023, 14:56

Verified outdrive ration, it's 1.50:1

With 17-3/4 diameter and 21p stainless prop I get 2000rpm and 24mph

Stringer Bell · 05 August 2023, 03:56

Well, turns out my turbo was sticking, and i ended up rebuilding it with new balanced cartridge assembly. Boat now gets to 2700rpm and 33-34mph

Gearing 1.5
Prop 17-3/4 x 21p ss

Huge improvement! Still way too shy of H733 speed. It will do for now for what i need

I will work on increasing fuel capacity in factory location

Stringer Bell · 05 August 2023, 03:59

Dis you have new tank made or fit a generic tank/bladder in the space? Do you remember dimensions of space? Would be nice to know before draining and pulling the tank out, tnx

skidoodog · 13 August 2023, 21:28

T cut my tank and extended it down. Now about 60 gallons. There are some pics on my 7m repower post. Check the bottom of your tank for corrosion. Mine was badley corroded at the back corner.

I had good luck with a 17.5 inch dimeter by 21p aluminum prop on my Konrad drive boat. 35 mph is all you are going to get from the stock 5.9 in my experience.

cheers Dave