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First Time Out on new SSX w/Mercury GT 115

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Jsvaughn

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Took our new 22ft. SSX out today for sea trials. Our boat has the Express Tube Package. I copied the engine break-in procedure out of the Mercury owners manual for reference. There were only two of us in the boat. Water conditions were calm. Owners manual limits RPM to 4500 for ten minutes with a one minute full throttle and then back to verious rpm's. This is for the first two hours. We could not get the boat up on plane at 4500 rpm. When I would go to throttle up for one minute the engine would surge and appeared to be hitting the rev limiter. I also thought the prop may be in cavitation. Trim was down. Only one time did we get the boat to plane. After nearly two hours of what I would consider "putting around" I stopped in the river and called the dealer for advice. First thing the dealer did was "freak out" that I had gone full throttle. I informed him I had followed the owners and he recommended against it. Said to just take it easy for first four hours. At this point I am getting confused. Needless to say, Our first outing was not much pleasure. After getting home I called the sales person and she says the motor will "monitor" itself until it is broke in and it was probably restricting the rpm. It has been years since I have owned a boat but I do know my way around the mechanics. The dealer assures me the prop size and pitch is correct. Any suggestions before I hit the water again. Thanks...... Steve
 
As far as break-in absolutely follow the Mercury manual's recommendation vs what the dealer said. You would have to be at least 6000 RPM before limiting starts on that engine, so if you're not revving that high it's not likely. I'm not aware of any "monitoring" for break-in period that would self limit RPM unless the new GT added this as a "feature", but it's highly doubtful.

If it's not planing at 4500-5000 that does seem like excessive cavitation such that the prop isn't getting enough bite, so it's possibly the wrong pitch, engine mounted too high, or a combination of both.

Fyi, here is an excerpt from another source with respect to Verado break-in and why WOT is used for that engine:

"We first have to start with the motor being cast. Once the block is cast all the mating surfaces have to be machined flat so they can accept their counterparts. During the machining, the cylinders are bored, honed and cross hatched. Cross hatching looks like the oil dipstick cross hatches but only very, very fine. When the cross hatches are made they leave very fine peaks and valleys in the cylinder walls. Now with that being said...... on a new motor that has not been run yet, the "peaks and valleys" need to be worn away. When metal gets hot, it expands and when it cools it contracts. When the piston moves up and down, the cylinder wears away at those peaks and valleys.  We all know that to break in a verado we have to run at WOT for one minute every ten minutes and also vary the rpm every few minutes. What this does is it heats up and cools down the cylinder walls and also helps seat the bearings. If we didn't break in the motor this way, there is a chance that the peaks and valleys wouldn't be worn away but instead they would "bend over" and cause glazing. If a cylinder glazes, it has no place for the oil to sit in and would cause a break down in the cylinder to piston connection."
 
What pitch and diameter prop are you using? Sounds like your dealer is an idiot and I would not be surprised if he propped it wrong too. Sounds like you are following the instructions correctly. I broke in the same 115, although it was several years ago. I broke it in just like you did. But then the motor started acting up and I traded it in. Just kidding. I did trade it in, but it ran perfectly.
 
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Go get a Black Max 13.75 x 15 and install it. See what happens. They are a little over $100. You should have a spare anyway.
 
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By the way, rev limit on my 115 was 6400.
 
Thanks for the information. I am still leaning to a cavitation issue. The dealer did tell me yesterday they will do whatever it takes to solve the issues. We live in south Louisiana. The dealer tried to tell me they size these props for best performance during a 95 degree hot summer day. Temps were in the low 60's yesterday. If I cannot get decent performance with only a 35 degree spread then I have a problem. The prop is a Power Tech 20150924-103-3. Also has MQF 3R13PM135. The motor foot has a label with 13/31 2.38:1 on it. All I can make out without doing some research is I have a 13 inch prop. Thanks for the Black Max recommendation. I may go that way. But first I am going to make the dealer sort out the issues. Again, thanks...... Steve
 
That's definitely the right approach with the dealer. Hopefully they'll get it sorted quickly and you'll enjoy your new Benny as we do. Good luck!
 
I've run my boat in 60 degree and 100 degree air temps and never noticed any difference other than wind chill making you want to back off the throttle.  I've also run in water 65 degrees up into the low 90s.  No difference.  Sounds like he's feeding you BS to me.

If the prop is ventilating (sucking in air from the surface) you'd know it.  Your motor will quickly wind up in RPMs and at the same time you'd lose prop bite and boat speed drops off very fast (as if the motor went into neutral).  It gets really noisy too as you can hear the motor exhaust since the water isn't muffling it anymore.  You'd know it if that is what is happening.  I've had it happen in turns and people who've never been on a boat know something isn't right.  If you really think that's what is happening, your motor may just be mounted too high.  Look at where the bolts go through your motor and through the transom at the top of the motor where it touches the transom.  If there's another hole or two in the motor above the bolts, your motor may simply be mounted too high.  Have the dealer lower it.

If it's not ventilating (or cavitating, which is technically different, but the same for this discussion) it almost sounds like a boat with too much weight if you can't get up on plane...  Is it possible you have a leak and a pontoon half full of water?  That would add a LOT of "unknown" weight.  Does the boat sit level in the water (side to side)?  My Express sits bow high in the water at rest, maybe 12-18 inches higher at the bow than the stern.  But it sits level side to side.  I had water in my center toon, and the boat sat lower in the water.

Which leads to a good tip that I learned the hard way:   Make a mental note (or better yet, snap a photo) of the waterline at the front and back of the pontoons while your boat sits empty at the dock.  Trust me, if you ever have a tube leak, you'll be glad you have a point of reference.
 
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I have about 3/8 of an inch gap between the top of the motor mount to the transom. I recall this being about right with what I read in the owners book. The motor is mounted as low as it will go.......as far as I can see. But what you describe is exactly what I think is happening. I have to ease into the throttle and keep feeding it slowly or else the rpm's shoot up and forward speed drops off. The dealer told me over the phone yesterday to power it on up to get up on plane and then back off. I cannot do that. As far as how the boat sits in the water. Everything is high. Side to side is the same and it does sit high in the front when at idle. We probably had about 375 lbs between myself and my friend yesterday in it. I had him move towards the front at one time but never notice a change of attitude in the boat. I also think the tach is not working properly. With the engine off it reads 1,100 rpm. I do recall the engine at 900 rpm idle yesterday so maybe it only functions correctly when the engine is running. I didn't notice if it went down to zero when I killed it. I told the dealer I would take it out again next week but I cannot see anything being any different. They may have to send a mechanic and prop out to the lake. Thanks. Got to get over this hurdle so we can start appreciating our new boat :)........ Steve
 
Which leads to a good tip that I learned the hard way:   Make a mental note (or better yet, snap a photo) of the waterline at the front and back of the pontoons while your boat sits empty at the dock.  Trust me, if you ever have a tube leak, you'll be glad you have a point of reference.

Thanks kaydano. Good tip. I hadn't thought about doing that
 
Went to the Power Tech Prop site and their recommendation for a pontoon in my HP range is a PT-TR04 which is a 4 blade prop. Mine has the MQF3R13 prop... 3 blade. My current prop says it is a match for the Black Max prop. Are you guys running 3 or 4 blade props.
 
Typically they are 3-blade on pontoons. Any chance you might have a spun prop hub or the prop is loose?

The tachs usually have a setting on the back for the number of poles/pulses, so perhaps it was not set properly for that engine.
 
Sounds like your motor is all the way down. Back to the drawing board...

I had a Spitfire 4 blade I was impressed with. Awesome acceleration, at the expense of loss of a little top speed. You are far from fine tuning a prop until you get this mess figured out. Making sure you have the right pitch prop is a good first step.
 
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I think I missed your earlier comment.  You mentioned you thought you had a 13 inch pitch prop.  That sounds like the right size for that motor.  That's what I had on my 115, and our boats are nearly identical.

From what you said, it sounds like your motor is in the lowest position, so that's not it.

Those were the obvious things to check, and sorry I can't help you more.  I have no other thoughts about why you are ventilating/cavitating and can't get your boat up on plane. 

One more thought - Is the motor shaft the right length for your transom?  I think they come in 20 and 25 inch shafts.  Surely your dealer would not have matched up the wrong motor to your transom size?  I think all the Bennington S models have the 20 inch transom, so that shouldn't be the problem, but it would explain the issues you are having.  Ask your dealer if the motor is the right shaft length for your boat.

Let us know what your dealer says.  Stories like yours will help a lot of people in the future.
 
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No offense but I think it is over trimming. This happened to me with my first toon and 115.
 
kaydano said:
I think I missed your earlier comment.  You mentioned you thought you had a 13 inch pitch prop.  That sounds like the right size for that motor.  That's what I had on my 115, and our boats are nearly identical.

From what you said, it sounds like your motor is in the lowest position, so that's not it.

Those were the obvious things to check, and sorry I can't help you more.  I have no other thoughts about why you are ventilating/cavitating and can't get your boat up on plane. 

One more thought - Is the motor shaft the right length for your transom?  I think they come in 20 and 25 inch shafts.  Surely your dealer would not have matched up the wrong motor to your transom size?  I think all the Bennington S models have the 20 inch transom, so that shouldn't be the problem, but it would explain the issues you are having.  Ask your dealer if the motor is the right shaft length for your boat.

Let us know what your dealer says.  Stories like yours will help a lot of people in the future.
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Negative on the 20 inch shaft length for all "S" boats. Our 21SLX. Is a 25" .
 
My understanding is you can have a longer shaft motor (25) on a shorter transom (20)...

Is you motor 25 or the transom 25? Or both?

Andy, you could be right. I assumed it was basic knowledge that a prop trimmed up out of the water does not work so well, but maybe the OP doesn't know about the trim switch???
 
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Nothing to do with trimming the boat. Dealer contacted the prop manufacture today and they have the incorrect prop for my application. My sales person said the prop they installed would normally be correct but I my boat they put a "beefier" lower end which in my case requires a 14 inch prop with more pitch. They will have the correct prop in a couple of days and I'll have it installed and head back to the water. Hopefully, the correct prop will resolve the issues and our second outing will be much more enjoyable. I'll give an update as soon as I can. Thanks for all of the comments......steve
 
kaydano said:
My understanding is you can have a longer shaft motor (25) on a shorter transom (20)...

Is you motor 25 or the transom 25? Or both?

Andy, you could be right. I assumed it was basic knowledge that a prop trimmed up out of the water does not work so well, but maybe the OP doesn't know about the trim switch???
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Both transom and motor are 25. It's a part of the SPS package on the boat.
 
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