Tower of Power identification

[FFScott6]

Re: Tower of Power identification

COuple of things... I had a great summer with the Grady White and the "twins" outta the gutter please! I mean the Merc 115 L6

honestly I did not do much other than ensure fresh gas, clean seperator and plugs. I did find and replace some corroded ground wires on the motors, rectifiers, batt cables, rewired the perko bat selector, couple other odds and ends. L/U oil is in good shape no water or metal.

These motors scream! and take this Grady (21' Overnighter) to 35+ mph on GPS at somewhere around 4400 rpm's, I can stay on plane at 2600 - 3000rpm, roughly 18mph (depending on conditions). right now they are propped with 13 x 19's fixed trim and using bennett tabs (12"w), my best fuel economy/nice ride cruising is 3200 - 3600rpm's keeps me running around 24mph. my last 38mile round trip used approx 12gallons of fuel.

This winter I'm gonna do fuel pumps, clean carbs, new plug wires, maybe new control cables motor to helm (lots of questionable wire conditions), impeller & water pump, L/U oil change and new seal kit, I found a cracked swivel bracket and many on ebay/CL etc. to buy, split battery system (one to start & one to accessories), fuel sender and gauge... then onto the hull. That'll be another thread...

Safe & warm winter wishes to all...

 

[mr 88]

Re: Tower of Power identification

Nice that you had a good summer with the twins. It sounds to me like you are over propped with the 19's.Those motors do not like to be lugged and you should be closer to 55-5800 rpms @ WOT.Not exactly sure on the rpms for your model but I am sure it is way over 4400.I top out at 6G with my 1500. How accurate is your tach ? If you are indeed over propped when you put the correct ones on everything will improve... top end /cruise speed/ throttle response at varying speeds including hole shot to fuel mileage. Might want to borrow a couple 17's if tach is accurate.

 

[FFScott6]

Re: Tower of Power identification

Thanks MR88,
I have heard a couple of times over the summer I should try a couple of 17 props... There is a respected prop shop near where I splash. was thinking I could drop my 19's off for refinishing and "borrow" a couple of 17's to 'test'. I do get good throttle response and nice hole shots... Tachs - accuracey is a good question? plan is to do ALL new control wiring & gauges this winter so I'll know for sure in the spring. Back to the props, I have planty of get up to either fly over wakes & rough water (will get a nice shower) or a slsow cruise through them (preferred at my age).

??? why would both P/O's keep 19" props? This boat spent the the majority of its life off shore fishing w/4 - 6 crew and all the gear for a long day at sea. They routinely fished out in the canyon, ttrolling and drifting. Would the 19's give more torque for the load and trolling?

I get what you say about the "lugging" there is a definate very narrow window between water conditions, RPM and being able to stay on plane or plowing through. so for the recreational use to get from beach to beach and a light crew and gear (2 - 4 onboard) your suggestion would be to use less pitch. The boat wieght launch ready for a day out is probably in the area af 3000lb +,-. 21ft and 18" draft + lower units.


Thanks for the opinions/advice! iBoats has been great for me and I tell others.

 

[mr 88]

Re: Tower of Power identification

The PO may have switched props before selling , had it wrong from day one or misinformed.A lot of people think that by increasing the pitch that they will get better gas mileage,wrong. All they are doing is using more gas because you have to give them a lot more throttle to keep it at your efficient cruising speed.The 19's would give it less torque and trolling speed at near idle would be increased slightly.I would not put a penny into your 19's until you try some 17's.If the 17's perform better,which they will if your tach is close to correct,then carry the 19's for emergency or trade them as 19's are very commonplace.You should find out what your RPM range is for those particular twins and take it from there.It doesn't hurt to be under the max rpm by a couple hundred but 1000 is way out of line.

 

[79Merc80]

Re: Tower of Power identification

Max reccomended RPM for those are 5,000 - 5,500. Although MANY mechanics have said that they will easially go to 6,000 RPM. They also set mine up so that with just myself in the boat (No Gear) I was able to reach 5,900 RPM. With all the gear and other people, I was still able to reach 5,500 while towing a skier. They don't like to be lugged, but they don't mind going over 5,500 for short periods of time. Mine ran great at 4200, but just sang at 5900.

Craig

 

[FFScott6]

Re: Tower of Power identification

Thanks to both of you for the great insight. I am easing into the passion of boating (mostly cause it costs alot) don't get me wrong I knew it was going to cost money. I simply want to understand and know as much as I can before we take the plunge into this hobby with all our heart. This old Grady and these "Classic" motors are proving to be a great deal of fun, even with all the trials and tribulations.

I'll certainly keep posting here and iBoats in general so that others can benefit just as I have and will. We are hard surfaced for the winter so I have a few months to get my parts ordered and start the tear down and refreshing.

Thanks again!