posted 04-14-2015 09:37 PM ET (US)        

I just found out Whaler recommends a 28-inch spacing on these hulls [for engines that are] stern mounted. I am going to try the 28-inch centers.

How high off the stern are [the engines] recommended to be on a 28-inch center[?] Any help would be great.

posted 04-14-2015 11:38 PM ET (US)            

Do you happen to know the deadrise angle of the 27 OFFSHORE hull? I am guessing it is about 22-degrees. By moving 1-inch farther from keel center, the hull will rise only

1-inch x sin(22-degrees) = 0.374-inch

I will be surprised if the immersion of the gear case by 0.375-inch is going to be the solution to the propeller breaking out. The reason I say this: usually an engine mounted on a Boston Whaler would be mounted at 1-hole up or 0.75-inch up.

Give some details of the propellers you are using or have tried.

posted 04-15-2015 07:21 AM ET (US)            

I am using the Mercury MIRAGEplus with vent holes plugged up. I get 5,650-RPM out of the engines.

From what I saw at the natural [toe--but again not specified as toe-in or toe-out] when taking off the tie bar on a plane and letting it toe itself to going with a 1-3/4-inch tow. Started me thinking about how the water travels down the hull.

I have had three different sets of engines on this hull. All brand new engines, from OMC Ocean Runners 225-HP to BRP 250[Ficht] to BRP 250 E-TEC. After around 400 hours I start to get water in the gear cases on all of the different engines. That is one of the reasons I was thinking about spreading the engines to a 28-inch center. I have been to several dealers. We have looked at the hull. [There is] no hook in hull. [I have] put a straight edge on the hull. No one has found any [defect] with the hull or the height of the engines. One dealer said it might be the way the water is traveling down the hull and the gear cases might not be getting cooled properly so the gear case will heat up a little more and suck in very small drops of water. If this right, I do not know. I just know I need to find out why I keep getting water in the gear cases as well.

posted 04-15-2015 07:41 AM ET (US)         

Have you tried the Cyclone 4-blades or the Rebel series of propellers? My guess would be that either type would be an improvement over the abovementioned props.

What are your engines' model numbers?

posted 04-15-2015 09:14 AM ET (US)            

TOE-IN means the front of the gear cases are closer together than aft end of the propeller shafts. The wakes of the outboard engines diverge.

TOE-OUT means the front of the gear cases are farther apart than the aft end of the propeller shafts. The wakes of the outboard engines converge.

I am confused by what you mean by "slipping". Do you mean the propellers are ventilating and losing all thrust? Or do you mean you have calculated the SLIP and found it to be higher than you'd like.

If the propellers are ventilating and losing all grip, I would be surprised if a one-inch movement outboard from centerline would be the cure.

Do you have some data about the engine speed and boat speed for a particular set of propeller of a certain pitch? We could look at that data and see what the SLIP calculates to.

Are you monitoring the cooling water pressure on the E-TEC engines? What sort of cooling water pressure do you see when running on plane at high engine speed? How about engine temperature? Loss of water pressure and higher than normal engine temperature would be indicators of a cooling water problem.

I believe that Evinrude makes some different water pick-up screens for the gear case water pick-up. Using a different screen might help. Also, beginning about c.2010 the gear case on the V6 E-TEC engine began to have water pick-up inlets on the leading edge of the gear case.

Also, what gear case do you have on the E-TEC engines? There is a high-speed gear case called the LIGHTNING gear case. There is also a newer style gear case with a straight leading edge, called the MAGNUM2 or M2 gear case. The M2 has water inlets on the leading edge.

posted 04-15-2015 05:11 PM ET (US)            

One of my tie-bar bushings was gone, and [the tie-bar] had a lot of slop. I let someone else tell me what was going with the boat and in the stern, instead of looking at it myself. [Apparently has since installed a] new tie-bar and [set the engine to have] between 1/2-inch to 3/4-inch of toe-in.

Every time I have had water in the gear case, we changed the drive shaft seals. [The gear case} would be okay for around 300-hours, then water in the gear case, again. I have had a few [repairs] under warranty, but I still don’t know why [intrusion of water into the gear case] has happened to three different sets of engines, brand new, out-of-the-box, on that hull. I have a 31 OceanMaster with twin E-TEC 300-HP engine, and [have had] no problems at all with those gear cases. [The E-TEC engines] on the Boston Whaler boat have the M2 gear case. I have 2010 E-TEC 250-HP engines on the Whaler.

posted 04-16-2015 07:38 AM ET (US)         

The shift shaft o-ring is another spot that can hold pressure and vacuum while stationary yet possibly leak when in motion. Use a magnifying glass in the shaft area that rides along the o-ring and inspect for wear, ridges, and corrosion pitting. Also check for a bent shift rod that would put excessive pressure on one side of the o-ring.

Most of the time in situations like yours, a new upper driveshaft bearing housing and a new shift cover - both which come with seals installed - seem to take care of the problem, unless the propshaft bearings are very worn. Replacing those 2 bearing are very easy while the bearing carrier is removed.

Inspect both shafts for grooves or pitting that could affect the seals.

posted 04-17-2015 12:36 AM ET (US)         

quote:

---

I am going to change the seals on the drive shaft and propeller shaft.

---

posted 04-22-2015 08:40 AM ET (US)            

http://continuouswave.com/cgi-bin/propcalc.pl

A SLIP calculated at 7 is typical. There is nothing unusual about that amount of SLIP.

You originally said about your boat that, "I get a little slipping." You also said, "the port engine slips and has slipped since I got the boat."

posted 04-22-2015 10:00 AM ET (US)            

With twin Yamaha two-cycle 250-HP outboard engines on the same hull and spaced 32-inches on-center, the toe-in is about 3/8-inch. Hydraulic jackplates provide for 5-inch of lift. [The performance data above is for] Yamaha three-blade 13-3/4 x 19-M propellers, [an engine speed of] 5,750-RPM, [and a load of] two persons and 150-gallons of fuel.

I would sure try propellers before redrilling the transom.

posted 04-26-2015 11:56 PM ET (US)            

--there is no excessive propeller slip

--you no longer are planning on changing the engine mounting to increase the center-to-center spacing by 2-inches

--the remaining problem is only in regard to the failure of some seal in some part of the gear case of the engines.

posted 04-27-2015 12:04 AM ET (US)            

The failure of the AE-35 unit is predicted by HAL, the supervisory computer on the spacecraft. When the AE-35 unit is retrieved and tested, everything is fine. HAL suggests that the proper course of action is to restore the AE-35 to service, and wait for it to fail, as he predicted.

Your E-TEC M2 gear case seals are in an analogous situation. You are predicting they will fail in 300-hours. I suggest you run them for 300-hours and check them again. The changes you made to the engine tie-bar, both in the toe-in or toe-out (we don't know which) and to the repair of the loose fittings that were allowing the engines to rattle around, may have affected the gear case seal problem.

posted 05-01-2015 10:30 AM ET (US)            

Before remounting the engines with all the attendant costs associated with such a project I would absolutely eliminate ALL other possibilities.

Are you certain all the seals replaced on your lowers were fresh OEM parts? Are you also certain the mechanic working on your engines is fully qualified for the work? Has he had the factory training necessary for him to consider and eliminate any possible causes for the leaks?

From your reports it appears that your engines are well dialed in for optimum performance with your boat. I would almost rather pay to replace the seals every three years than change, so radically, my setup.

Perhaps another shop should be under consideration.

posted 05-01-2015 07:49 PM ET (US)         

On all your other boats/motors, were they treated the same and serviced the same?

Did these motors just start to leak, then you tested them? Or were they pressure tested before any signs of a leak and then they leaked?

posted 05-02-2015 11:37 AM ET (US)            

The notions put forth are as follows:

--a gear case should not require new seals after 300 to 400 hours of operation;

--the gear case lubricant has always been changed at 100-hour intervals

--the owner-operator has owned and operated other engines on other boats and not experienced this problem

--three different sets of different types of propellers have been used