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Posts: 3518
Location: north central wisconsin | OK, I need help. Just got the motor put on the ranger 690 Tiller and we're have a bit of trouble getting it propped correctly. Someone recomended that we run a 4 blade Yammy stainless with the motor on the top set of bolt holes. The dealer tried it and said it was ok, but lacked hole shot and top rpm(could only get about 5400 out of 6000 recomended apparently). So, after trying a couple of other props, they put the stainless job from my old Merc on it. I think it is an 18P but not sure. They left it on the top set of bolt holes and told me hole shot was fine and top end was great. Well, I got it home yesterday and I am not happy with it yet. The hole shot is worse than my old motor, and the boat wants to porpoise now at certain speeds, even trimmed all the way down. It is very touchy at other trim settings too. I am hoping to get it right this week when going in for the 10 hour check. Now, I haven't had it at WOT on plane due to the break in, but I don't really care if I lose a degree or two at top end, as long as the thing will plane out better and just handle better at running speed... Another thing, there is a considerable amount of torque in my tiller hand when running. Can the trim tab halp some of this? the old motor didn't seem to have as much torque on my wrist. I know that it is a work in progress, and I am not mad at the marina, as they told me to try it and let them know how i felt when I came back. I've been told the Merc. Vengeance 16p prop is a good one for this application... Any recomendations will be greatly appreciated regarding prop selection and motor setting. Thanks in advance.
Edited by Reef Hawg 9/3/2007 4:08 PM
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Posts: 378
Location: In the slop! | Reef Hawg, you should be able to get rid of the steering torque with the trim tab. Not sure on the other part of your problem. Possibly setting the motor down a hole or two on the transom would help. Of course if you can do this yourself it's much better. It can be real frustrating trying to dial in a new set-up. |
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Posts: 80
| Reef Hawg I am not comparing apples to apples here but I have a Skeeter 1775t with an 80 yammy four stroke on it I have five batteries and a TON of gear in it so I think we would be relatively close in weight, anyhow I have a merc vengance 16p on it and the motor is in the top hole it planes pretty good fully loaded with three guys and excellent with me and the dog. Solo I am getting about 5600 @ 39-40mph three guys about 5300 and 33-34mph. Mine is a porpoising SOB when trimmed out not bad trimmed down a little I find it can be heavy on the arm on long runs as well. Dont know if this will help at all. |
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Posts: 3518
Location: north central wisconsin | Thanks guys. I just question the top hole placement. I have now been told that the cavitation plate should be about even with the keel. It is a fair distance above. Maybe I'll try dropping it some, and go from there. Again, just realy concerned with the hole shot right now. I'll worry about top end later on... After dropping the thing, maybe a lower pitched prop than the 18(again, I think that is what I have but not positive) will be needed....?...
That said, dropping the motor looks to be a fun job.....UGGHH!
Edited by Reef Hawg 9/3/2007 7:30 PM
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Posts: 5874
| Changing the motor height is not a tough job. I've helped, and seen it done in parking lots. You'll need the trailer off the tow vehicle, the wheels chocked, and one or two friends. Lower the tongue jack, and place a board under the skeg. Raise the jack until the weight of the motor is just off the transom. Take out the lower bolts, and loosen the top bolts. Have your friend hold the motor steady, and remove the top bolts. Have the other friend lower or raise the tongue jack to the desired hole. Put the top bolts in, put on the nuts, snug them up, and then the lower bolts. Don't foget to put new marine RTV on the bolts. Torque all the bolts, and you're good to go.
I don't think that 4 stroke will ever have the hole shot of the two stroke you had on it, without sacrificing top end. Not a knock, but just so you are prepared for that. |
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Posts: 5
| Why not let the marina use their electric hoist to move your engine? It will save some hassle on your part. |
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Posts: 395
Location: NW WI | I would go here:
http://www.wmi.org/multi_boards/props/index.html
and put up a post for Rich Boger, tell him what you've done and the results. Lots of these bass boards have their own prop guru's, but IMO this guy is honest, get's straight to the point and tells it like it is....like it or not. Knowing Rich like I do, he'll likely tell you to get some kind of Mercury prop. Check out his website too for more tips....www.bogerprops.com
Could Ranger get you steered in a better direction? Care to say what dealer sold you the motor? Just curious. |
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Location: Contrarian Island | reefer, that 4 stroker is never gonna have the hole shot of a 2 stroke...are you drag racing that 690 anyway?
but the added gas mileage, ease of trolling and quiet factor will make up for it..plus it doesn't say "mercury" on it!!  |
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Posts: 3514
Location: Elk River, Minnesota | Hi Reef Hawg,
First of all, I would agree that I think the pitch of the prop is probably too high, which, when you try to trim and you are not at the high end of your RPM range the boat will tend to porpoise...the motor is not generating enough power to keep the bow up, or it is not keeping it's bite on the water.
I would suggest trying a lower pitch prop first before lowering the engine height. Most V-hull boats run better when the anti-ventilation plate is roughly 2 inches ABOVE the lowest part of the transom. Most boats are set up so the plate is even with the bottom of the keel due to people just wanting a boat that gets them from point A to point B and nothing more. Problem is, with the lower unit THAT low, the boat will NEVER reach it's full potential for efficiency.
Going to a lower pitch prop on that rig will definitely help hole shot, and it will probably also take care of the porpoising as well. I would suggest trying an aggressive steel prop like a ballistic which allows you to run high motor settings yet grab well. It will also keep your RPM's up more than other steel props because the blades are thinner. They are still tough, but with any prop strike at speed, you will see damage (aluminum or not) with that motor in particular, getting your motor to 6000 RPM when the boat is lightly loaded is going to give you the best overall performance in all situations.
I have a 90 2 stroke on a 1000 pound boat, and granted it is 2 stroke, a 17 pitch does really well for me.
On a side note, if you end up moving your motor down, please DO NOT remove the lower bolts to make the height adjustment. You can use the method mentioned, but if you remove the lower bolts, there is a higher probability of the motor falling. We're talking 370 pounds balancing on a small block of wood and ALL of that weight on your skeg.
Block the motor as stated, then remove the top bolts. Loosen the lower bolts enough to allow the motor to move. Then, crank the trailer jack down to raise the rear of the boat to the point where you can re-insert the upper bolts. silicone and tighten. You're all set. It is not as hard as it sounds at all.
Keep us posted...
Steve |
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Posts: 3518
Location: north central wisconsin | Well, I(before reading VMS very informative post) decided to move the motor down two holes before changing props. It seems to give just slightly better hole shot, and porpoising was reduced quite a bit. She hummed along yesterday with two big dudes and all of our Musky gear at 38.1 top end. I think I can afford to lose a bit of top end. Brad, no not drag racing, but it is more important to get onto plane in 90% of the locations I fish, vs. top speed. I might just try a 16 pitch on the rig, then go from there. We used a comealong on the joists of the garage and moved the motor down no problem(leaving the bottom nuts on the fixed bolts).
I bought the motor from Mid state marine in Fremont and they've been very helpful thus far. They sell Skeeters and Yar-Craft and set them up a certain way.
Thanks again.
Edited by Reef Hawg 9/7/2007 3:58 PM
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Location: Contrarian Island | I'd suggest trying that "edge" hydrofoil my buddy has on his 690...might just do the trick....
I will check where he got it...overtons.com, stainless steel for 100 bucks...
Edited by MSKY HNR 9/6/2007 9:28 AM
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Posts: 395
Location: NW WI | Adding a hydrofoil is nothing but a band aid. A correctly setup and worked over prop will get you most of what you want.
You might have been happier with an Opti, Etec or similar......sorry had to add that.
See what Rich Boger says.
Just trying to help!!!! |
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Posts: 3518
Location: north central wisconsin | Thanks will check with Rich. Actually, don't like my dads etec 90 much, and wouldn't own an opti. Love how quiet it is, how smooth it trolls, and the top end. Just need to get the thing propped right I guess. That said, the hole shot wasn't the best with the merc 2 stroke I had, probably because the guy had it propped for speed. Will try some others and report back.
Edited by Reef Hawg 9/7/2007 3:56 PM
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Posts: 385
| Reef Hawg, is your Yammy a long shaft? I have one on my 618T and love it. I can look to see what prop I have on there. I know it's a merc prop and a four blade. Only issues I had were torque. The trim tab adjustment eliminated that. Mine is mounted in the top hole and the ventilation plate is dead even with the keel. |
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| HI Again,
Another option before a hydrofoil would be to have some transom wedges installed behind the motor. They can be placed in such a way to allow the motor to have more negative trim (tilted in at the bottom more) which should allow the rear of the boat to come up faster.
My hole shot was similar to yours (bow very high and a little sluggish) but going up with the motor took care of that for my rig.
No matter what you do with set-up changes, there will always be a compromise somewhere beit speed, handling, or holeshot. The key is to find that "happy medium" which takes time and energy...and we all know that sometimes those are at a premium.
If you like to tinker, playing with setups are fun. If you don't, it can be a real pain..
Keep going on it...you'll get there..
Steve
By the way...it sounded like things did somewhat well with the motor change...
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| I should also mention that hydrofoils seem to be more prevalent on tiller rigged boats...many due to the fact that tiller boats are rated lower for HP than console models. Thus...less power. It takes more to get the boat on plane and keep it there.
That may be an option for you if you would like to keep your speed down but stay on plane. Caution, though...if you go with a higher motor setting, the hydrofoil may not do what you desire since the anti-ventilation plate will be out of the water already. Again, this will depend on where you like your motor on the transom for your style of running.
In most cases that I know of, hydrofoils help rigs the most when they are significantly under powered. In your case, I am guessing the motor is max...
Steve |
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Posts: 3518
Location: north central wisconsin | yes, my motor is max, but underpowered greatly. The hull itself is rated for a 175 if a console...
I was told that moving the motor down would give me a better hole shot. Really hasn't changed much other than I seem to not porpoise as much nor does it blow out on a turn now trimmed down.
Matt, do you have the little set back in your boat, ie does your transom come down then go back and drop to where the plugs and then keel/actual bottom of boat are? When I had the motor on the top set of holes the plate was even with the bottom of the transome where the motor is mounted, but not even with the keel as it is now on the second hole up. It is a long shaft I beleive. We tried the 4 blade at the top set of holes and it wasn't so good.
Anyhow, I think I'll play with a different prop first. that shimming idea is good and I actually asked my partner yesterday if he thought it would be possible to do it. I don't want to mess with something after market that could screw something up.
Thanks.
Edited by Reef Hawg 9/7/2007 3:56 PM
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Posts: 385
| Reef Hawg my 90 is on the top hole and the ventilation plate is dead nuts even with the bottom of the keel where the drain plug/actual bottom is located. I'll have to check on the prop when I get home. Hope you can figure it out. |
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Posts: 3518
Location: north central wisconsin | Thanks. your hull must be a bit shallower than mine as mine is dead even with the bottom 2 holes up now. I just orderred a Power Tech 16 pitch from Mike at Precision Propellor in Brainerd MN after talking to alot of techs, and you dudes. he said this prop should allow me to raise it back up a notch... Will report back in a couple weeks.... |
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Posts: 3514
Location: Elk River, Minnesota | Hi,
this is just one website that has them... I have not done any business with them..just did a quick google search.
I bet if you look around a bit, you may find different prices, and locations to get the wedges from.
http://www.midtnmarine.com/products.asp?cid=Jack+Plate+Aces...
Steve |
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Posts: 385
| Reef Hawg, mine is a 17 pitch 4 blade Trophy .
Edited by Matt Collins 9/9/2007 4:45 PM
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Propping my new Yamaha 4 stroke 90...