1993 Force 120 Slipping in Forward Gear@Hi-speed

[TrophyFish'n]

I have twin 93 Force 120's and they run really great, very well maintained, however I'm noticing a problem. It seems to occasionally when running at above 10mph and around planing speed to even higher speeds like 30-35mph it will seem to slip while in gear as in the rpm's go up and the engine sound gets faster but the speed stays the same. I've noticed that this will happen a little more when the boat is near plane speed probably due to the higher torque required there. It's not the props as I have switched them out to brand new ones. I usually have to slow down put it in neutral and then shift back into forward and try it again. Sometimes it will run for 20 miles without a problem offshore but then it will start to happen so it's hard to predict. It seems to happen more with heavier load in the boat but it will still happen with a lighter load too. Since I've replaced the props (it's a twin 120, bayliner trophy 23 walk around cabin and both engines do the same thing from time to time), I believe it's something in the lower unit like the clutch mechanism being too weak or something. I'm seriously thinking about tearing down the lower unit and worse comes to worse get a rebuilt unit for about $1000 to $1300. Will probably have to do both of them but will try one unit at a time. What does everyone else think? Anyone else come accross the same type of problem? I've replaced the lower unit gear lube many times and have never seen any metal debris. The oil is always in pretty good condition however I've only owned the boat about a year and there's no telling what has happened in the past. Thanks<br />TrophyFish'n

 

[roscoe]

Re: 1993 Force 120 Slipping in Forward Gear@Hi-speed

If you are SURE the prop hubs are not spinning, I would look to engine mounting height and trim position before doing anything to the lower units. Sounds like the props are ventilating - either motor mounted too high, trimmed out too far, or some hull obstruction (transducer ?) is introducing air into the water as it enters the prop area.<br /><br />If the clutchdog is jumping out of gear, it usually makes some chattering noise, gets progressively worse, and leaves metal shavings in the lube.<br /><br />You might want to post this in the boat topic forum, as I don't think it is a motor repair issue, you will get greater exposure and more advice on the boat forum.

 

[DJ]

Re: 1993 Force 120 Slipping in Forward Gear@Hi-speed

What wiide open throttle RPM's are you getting?<br /><br />You may have upped the prop pitch when you changed them causing allot of stess on the prop hubs.

 

[zindale]

Re: 1993 Force 120 Slipping in Forward Gear@Hi-speed

was having same issue with mine after a lot of $$ finally came down to clutch dog and forward gear slipping edges of gear are not square slightly rounded. i tore lower unit apart and flipped clutch dog around and retried problem gone but not solved gonna retear apart and have remachioned square. clutch dog easy to remove but forward gear is a bear. just my 2 cents worth.

 

[TrophyFish'n]

Re: 1993 Force 120 Slipping in Forward Gear@Hi-speed

Thanks for the replies..<br />Brand new props, same pitch and diameter. Same original setup from Bayliner when built in 93. I believe this is getting progressively worse and I first noticed it after a tough day fighting choppy seas at about 15-17mph. This is right around planning speed and requires the most torque to fight against the drag. I noticed it this day and it sounded like a prop spinning and the rpm's were going to 5k instead of staying at 3500 or 4k, etc. I always had to lower the throttle down to neutral to remedy it but sometimes it would jump back out and other times it would be good for the next 20 miles. Seems to be more frequent now. In my opinion I don't believe that air is getting to the props. This can happen in calm seas and before getting on plane or it can happen in rough seas either way. When the gears stay engaged the rpm's are rock solid even when the boat is getting air off of waves at 30mph. Other times it rev's up and I can give it more gas and all it does is reve higher to 5500 or so.. If I don't bring it down to neutral it will stay there so this tells me it's not air or turbulence. Otherwise eventually the prop would hook up. <br /><br />I will see if anyone else has the same problem but I am curious if I were to take this lower unit apart would I see some rounded off edges on the gears or not. It does make sense to me as a rounded edge would intermittently have good contact but under high torque the gear could let go and it's kind of random may or may not happen depending on initial engagement of the gear from neutral and what vibration is going on.<br /><br />Other than that these engines work great when they're hooking up. I just need to get them so that I can do some longer distance fishing. So far it seems I have no problem trolling around at 6-10 mph or so as the gears never disengage at this low speed.<br /><br />Rgds.<br />TrophyFish'n<br /><br />

Originally posted by zindale:<br /> was having same issue with mine after a lot of $$ finally came down to clutch dog and forward gear slipping edges of gear are not square slightly rounded. i tore lower unit apart and flipped clutch dog around and retried problem gone but not solved gonna retear apart and have remachioned square. clutch dog easy to remove but forward gear is a bear. just my 2 cents worth.

 

[roscoe]

Re: 1993 Force 120 Slipping in Forward Gear@Hi-speed

Like DJ said, What are your WOT rpm's?<br />Wouldn't it make sense to at least test the props before tearing the units apart?

 

[Darren Smith]

Re: 1993 Force 120 Slipping in Forward Gear@Hi-speed

I have to agree with roscoe and zindale. Have you indexed the props to make sure they aren't spinning? Even though they are new it can happen. I doubt its venilating if you haven't changed to motors and they are at factory settings.<br /><br />And welcome to Iboats!! Nice boat...good choice <br />P.S. do you have 12 5/8 x 21P cupped props?

 

[TrophyFish'n]

Re: 1993 Force 120 Slipping in Forward Gear@Hi-speed

Roscoe: WOT rpm's are about 5k or 5200 from my memory, not sure to be exact. Rationale why I think the props aren't spinning is because the lock washer that you bend down onto the prop has not moved. In order for the hub to spin you would have to spin this lock washer and the tangs would have to pop up to do it. The rubber is between where the tangs mate to the prop and the splined shaft. There is no evidence that the nut turned inside of the lock washer. If it did it would look spun and that's not the case. I agree however that it would be good to mark both pieces and give it a try for final verification. Just have been too tempted just to go out and go fishing! Who can blame me.<br /><br />Knot Addicted: Cool another 2302 Trophy with twin 120's. I knew there had to be mroe than one. I'm sure we could share some interesting info. In all honesty I like the boat. I have had my share of problems but I think I've got it mostly under control aside from this lower unit issue at the moment. I'll have to get back with you on the prop size and pitch. Will get it later. Thanks for the replies.

 

[roscoe]

Re: 1993 Force 120 Slipping in Forward Gear@Hi-speed

You are supposed to bend the tab washer tabs outward, toward the nut. It defeats the purpose of having a prop hub if you are going to bolt it all together.

 

[Darren Smith]

Re: 1993 Force 120 Slipping in Forward Gear@Hi-speed

Roscoe, on that model, the tabs are bent inward to the indents on the keeper. The keeper is splined to the shaft, so it will not turn. <br />For this motor, there is the thrust washer, then the prop, then the keeper washer, then the tabbed lock washer, and lastly the nut.<br />To index the prop to check for slipping, scribe a line from the prop hub, across the rubber bushing, to the prop housing. The washer (keeper)will stay in the same place on the shaft, but I would reccommend scribing the hub, not the keeper. I'm still thinking it sounds like the clutch dogs though.

 

[TrophyFish'n]

Re: 1993 Force 120 Slipping in Forward Gear@Hi-speed

Ok. No problem I can scribe it and take it out for a trial run this weekend. I have 13x19RH props. Here's the million dollar question however. Let's say I am spinning props still even with two brand new props with new rubber bushings. What is the solution then? Do I have any options? Somehow I don't believe that is the case but I'm not saying it's not possible. I've got 13yr old engines that have probably seen their share of abuse over the years. So I'm kind of siding to the worn out lower unit but I agree I don't want to break out a thousand dollars unless it's absolutely necessary. That stuff doesn't grow on trees! Now that I look at the design of the new props I can see that the tabs fit into the inner hub and not the prop itself. So yes it could spin and I wouldn't know about it. I'll have time this weekend to scope it out. During the week it's hard to work on as I keep the boat in storage away from the hacienda. Rgds..

 

[roscoe]

Re: 1993 Force 120 Slipping in Forward Gear@Hi-speed

Some boat/motor combinations are going to be more prone to spun hubs.<br />Full throttle hole shots will spin some prop hubs on brand new props. Especially if pushing a heavy load.<br /><br />Seems strange to me that clutchdogs would go on both motors.

 

[Darren Smith]

Re: 1993 Force 120 Slipping in Forward Gear@Hi-speed

In your above post you said new rubber bushing, are you using the Mercury Flo-torque interchangable hub system, Or regular 1 peice props? If its the Merc system, could it be that you aren't getting the prop nut tight enough? Thight might allow a slippage like you are describing. Also, it might be time to double check the shift cable to make sure they aren't stretched, and not fully ingaging in gear. Don't know why I didn't think of that before.

 

[TrophyFish'n]

Re: 1993 Force 120 Slipping in Forward Gear@Hi-speed

I wrenched up the props to 50 ft-lbs via a torque wrench. Just looked up the spec in the manual and it says 55 ft-lbs. I doubt the 5 lbs will make a difference there. I'm taking it out in the morning and will see how it turns out.<br /><br />I will wrench in another 5 ft-lbs as well + the scribes.<br /><br />Will have to check the cable if it happens on the water to see if I can see any change there.<br /><br />Props are using the interchangeable hub system with the new props. The previous props were 1 piece Stainless. The new ones are aluminum.<br /><br />Thanks

 

[Darren Smith]

Re: 1993 Force 120 Slipping in Forward Gear@Hi-speed

Was this problem hapenning before you changed the props to the interchangeable hub? If not, it sounds like the hubs may be suspect. You might want to try the old props to see if it still does it. Hopefully it isn't the props, because I just bought Michigan Wheels XHS... I'd hate to find out that it has issues.

 

[TrophyFish'n]

Re: 1993 Force 120 Slipping in Forward Gear@Hi-speed

Ok. The problem happened on the Stainless props with a really full load of gear, fuel, and people. On previous trips there was minimal slippage because we had less weight and flat seas. New aluminum props are the same. Torqued the props up to 60ft-lbs for saturday. Took it out in the gulf 10 miles and had the problem occasionally but was always able to get it to hook up eventually by bringing it back to neutral and or reverse and applying forward again. Checked the hubs/props afterwards. Scribes did not move. Did lose preload on the starboard nut and the lock washer moved. The scribe on the hub to the prop were the same but the nut had moved. (Have not been able to get a new ny-lock nut yet as the boat store didn't have my size when I bought the props. In any case this tells me the props aren't slipping. Sure I need some new nylocks but that's pretty simple. I'm going to order a gasket set for the lower units and see if I can inspect the lower unit parts for any damage. Worst case scenario is sending in the lower units for trade in on a remanufactured lower unit. Best case is that I can somehow remedy the lower units somehow. Maybe adjusting a shim or something. I'm doubtful on that but who knows what do I have to lose. I don't think the Michigan Wheel props have issues. Seem to be pretty decent props. Also I tested WOT and got about 41-42 mph at 5100 rpm and 4900 rpm. One tach reads lower than the other. <br /><br />KnotAddicted- Does that sound similar to your setup? You ever had any problems with your 120's or your Trophy? I've had a stringer problem pull out of the hull wall which caused the starboard hull to bow out a little more than normal creating a spider crack. Repaired the outside and the inside. The inside required gap filer and glass layers overlayed on the stringer and the wall. Rock solid now. It's basically right where the walk around meets the back deck. There's a beam that runs across from port to starboard there under the floor. If it pops out from the wall on the hull, then you will start to get some cracking on the outside right there. It's probably that type of thing that gave bayliner a bad name but I can't complain now that I've got it repaired. It's pretty solid and still a good looking boat.<br /><br />Rgds<br />TrophyFish'n

 

[Darren Smith]

Re: 1993 Force 120 Slipping in Forward Gear@Hi-speed

TrophyFish'n, since I have only had mine for about a month and a half, I have been trying to take care of the initial set ups. I bought it in Miami, and shipped it to Panama. So far, I lost one of the motor trailer supports, and ground the skeg pretty good, and messed up the prop. I bought 2 new props, 12 3/4 x 21P. I finally got the boat out last Saturday just to find out I probably should have got 19P. WOT was about 4500 and 35 MPH. I also found out that neither engine is charging, so I ordered 2 rectifiers. Waiting for those now. Only other things I noticed, I get water in the front cabin floor, don't know from where. And the live well doesn't drain fast enough to keep it running all the time, so I have to shut it on and off, or it over fills. That might be where the water came from, but have to dig into it more. I haven't noticed and stringer prob's yet. I do have a railing that I need to straighten, but can't figure out how the screws are anchored, they turn, but don't come out. I also need to adjust the idle, right now they die in neutral... the list just keeps growing But it was the type of boat I wanted, small enough for the lake, and large enough for the ocean, cabin for the admiral, and lots of fishing space for me!

 

[TrophyFish'n]

Re: 1993 Force 120 Slipping in Forward Gear@Hi-speed

Trailer motor support. I'm guessing you mean the stainless support that supports the engines trimmed up to provide clearance while trailering. Yea those are kind of useful. Haven't lost mine. <br /><br />If the previous owner didn't replace any of the ignition components, you probably should replace everything since after about 10yrs you're going to get electrical shorts or opens from the fact that the insulating material wears out over time. My previous owner replaced all that with new components. I think he spent about 3k total. So my engines run like champs now. It's basically like having to replace the plug wires in your car about every 100k miles or so. They wear out with the heat exposure and just the time exposure to the air.<br /><br />Water always gets in the front of the boat under the floor. (not much unless there's water in the front fish box) Just a fact of life. My floor is cut out right there probably due to water standing in it. That floor is about 3/4" thick. Below it is the hull which is a lot thicker fiberglass. It's hard telling where the water comes from. Although it depends on what angle you store the boat. Try to store the boat with the nose up as high as possible to thoroughly drain the water. There are holes in the stringers to allow water to pass from front to back under the floor. If you store the boat level or close to it then you may not get total drainage of the water out of the boat. It should stay under the floor if the boat was dry to begin with. I have found the forward fish box on my boat at least drains into the hull so that could be a possibility. The 2 back ones are connected to a fish box pump. My live well doesn't work although it used to. Not sure why. Really I don't care as long as it's not bringing in water. It's too small and I find that a 5 gallon bucket with a D cell powered aerator is better plus it won't run down your battery.<br /><br />I've been to Panama a few times and through the canal as well. I'm sure the fishing is good although I never have fished there. <br /><br />The screws on my railing mount on the bow are the same but it's not a big concern. I don't plan on repairing them until I need to. My only real issue with the boat is the lower units. Will be happy once I get this figured out so that I can cruise without problems.<br /><br />Rgds

 

[TrophyFish'n]

Re: 1993 Force 120 Slipping in Forward Gear@Hi-speed

If you store the boat outside and it's not covered rain water will be getting into the boat. If it's not angled up than water can stand in the cabin. I've seen it in my boat from that situation but never on the water. I always try to store it with the nose up and with a cover or inside.