New 50HP Four Stroke Questions

[OldMech]

I just bought a 2016 50HP Four stroke... after going to the dealer to look at a used motor they had... Decided the new one was the way to go... except... I run the rivers, always, sometimes for a week straight, meaning, day and night, running bank lines etc.. I put my custom built toon in the River today to test the motor, and *** is that nice!!! Quiet and powerful. I am in love!
As stated, the purpose of my boat is catching big cats, day and night.... If you have ever run the rivers you KNOW your going to eventually hit a log/snag you didn't/coundn't see... this motor has trim and tilt, and it was my intention to unhook it completely, and use the bungee system I have always used on my smaller motors in the past... Will this motor kick up or am I going to rip the lower unit off the motor and the transom out of the toon if I leave the trim hooked up?

Question two. Oil. My Motor came with synthetic oil, and I was told to run only suzuki oil in it.. is this to sell more oil or is there something different about it that GOOD synthetic automotive oil wont cover?

Question three. Prop.. I have an 11 pitch prop, and at WOT the RPM's are right at 5000 is that OK? Do I need to drop to a 10 pitch to get closer to 6000?
I have no complaints with how it handled or ran, but want to break it in right. I will seldom be running WOT, not a wise thing to do on the river... I ran it today at WOT for 40 min upstream and about 20 min down stream because the river is up and I had "little" fear of hitting anything... but the day is coming... and i dont want it to be a day of tears. Thanks!
OldMech

[artdf175]

Not familar with the 50 hp
But Q1 probably has to do with weather it is hydraulic trim or not
If while in forward gear (not running) can you by hand tilt the engine ?
That will tell you if it will kick up upon hitting an object
And i suspect you have a prop guard? Trust me hitting something with a prop running at higher RPM's can do a lot of $$$ worth of damage
That beings up a question - if you are running rivers that have logs/ rocks why did you by a prop drive vs pump?
Q2 a good synthic that is rated for outboards would be important
Q3 prop it is my understanding at WOT you should be able to hit 5800/6000
Art

[OldMech]

But Q1 probably has to do with weather it is hydraulic trim or not
If while in forward gear (not running) can you by hand tilt the engine ?
That will tell you if it will kick up upon hitting an object

I assume it is electric over hydraulic, and I have not pulled HARD on the engine to see if it will lift, but it does not budge with mild pressure..
So I am then assuming I need to remove/unhook the trim/tilt system. I find it difficult to understand how anyone could run a system that is unforgiving.. I used to live in the Keys, and even there I saw people occasionally hit underwater objects. I have lived in Maine for 17 years, and both in lakes and on the ocean, I saw boats hit things.. There is a high chance that sooner of later it IS going to happen even to the best of us... So, WHY would anyone put something on a motor that guaranteed its destruction? (And possibly a lot of damage to the boat) Very disappointed and unhappy with Suzuki at least with this aspect.

And i suspect you have a prop guard? Trust me hitting something with a prop running at higher RPM's can do a lot of $$$ worth of damage
That beings up a question - if you are running rivers that have logs/ rocks why did you by a prop drive vs pump?

I have been running the rivers, lakes and oceans for 45 years so I have a "tiny" bit of an idea what happens when you hit something, which is why I am inquiring about the motor tilting up, and no, I have never used a prop guard, I just buy good stainless steel props.. No rocks, just the occasional submerged log/snag. The reason I dont buy a jet is because both dealers I spoke with told me they would not last if I ran them in the river due to the mud/sand/debris. I was also told it would not handle/steer or reverse as well if used on a toon. I actually intended to buy a jet until then.


Q2 a good synthic that is rated for outboards would be important
That does not answer the question. I have been a mechanic all of my life so I think I can handle it if you throw out the technical lingo.. if it makes my eyes water I will apologize for asking! If no one can tell me WHY the marine oil is better then there is a very high likelihood I will be using a top brand automotive synthetic oil when I do the first oil change.


Q3 prop it is my understanding at WOT you should be able to hit 5800/6000

Thank you, I will drop a pitch and try it again. I do appreciate the reply, even if I am not happy with the answer, (or with Suzuki now)
Scott

[Solarman]

Yes, generally your outboard will break away and be thrown up, in the event you hit something, although at higher speeds I have heard damage can still be done if the log/debris hits too high on the leg. So it might be advisable to keep tilted as high as possible when you're in waters where the risk is higher for hitting something.
Question on oil. An outboard quality synthetic oil should be used in the lower unit due to cooler operating temps, being submerged in water. However, I believe the synthetic oil used in the crankcase can be a good quality automotive synthetic. Just make sure it won't affect your warrantee, no need to have those problems.

Good luck.

[OldMech]

Yes, generally your outboard will break away and be thrown up, in the event you hit something, although at higher speeds I have heard damage can still be done if the log/debris hits too high on the leg. So it might be advisable to keep tilted as high as possible when you're in waters where the risk is higher for hitting something.
Question on oil. An outboard quality synthetic oil should be used in the lower unit due to cooler operating temps, being submerged in water. However, I believe the synthetic oil used in the crankcase can be a good quality automotive synthetic. Just make sure it won't affect your warrantee, no need to have those problems.

Good luck.

Thank you Solorman. This toon does not go fast, nor is it meant to go fast, but its still a lot of weight to try to stop suddenly. I have inspected the trim set up pretty closely, and see nothing mechanical to release. I found a screw on the side that apparently will allow the hyrdaulics to bypass? But then the trim and tilt will not hold, or even work depending on where I back the screw out to. is there an actual hydraulic valve/bypass that opens to let it kick up?



Thanks!

[ChrigelKarrer]

Well,
if your experience tell you that your way to solve the problem with hitting obstacles is the right way, the do it.
At this point i would lift the engine all up, set it on the locks and disconnect the tilt piston, retract the trim/tilt pistons all in and leave them there disconnecting the trim switch cable.
The problems may be:
a) the engine hit the trim piston when all down
You will need to create a spacer that the engine can't go all down, but then the engine can't be tucked in, in case of problems wit bow rise you would need transom wedges.
b) you are most likely not able to tilt the engine out of the water when not in use.
There is a tilt tube handle to help you tilt the engine up, this may be a solution.

Keep in mind that your new 4 stroke is heavier than your old 2 stroke and this will make it harder to kick the engine up.

Suzuki write in the big engine manual thet synthetico oil should only used after 200 hours. Check your manual regarding this matter!

Yes, you have a manual trim release screw and opening it may do the trick,
but this may lead that you loose the screw (as she should be normally tight in closed position) or water enter your trim system and ruin it.
But still, as the oil in the trim has to be displaced when you hit something, the oil passing thru the release valve will be slow and dampen the kick up.

5000 rpm WOT is too less and you will "lug" your engine, every 2 inch less pitch will make you gain 200-400 rpm.
You should check your engine height, a too low mounted engine will create drag and thus lowering RPM.
For your heavy, slow boat a 4 blade propeller may work much better,
if you want more specific information regarding your propeller please do a testdrive with your usual load and post here the speed for every 500 rpm from ideling to WOT. This will show how your propeller is working/slipping!

Chris

[mrpister]

That looks like the AV large gear case version of the DF50. That explains the prop pitch.

[OldMech]

Thank you ChrigelKarrer. The engine mount frame has holes for a trim pin, so I can install one to set the engine at the right angle, hopefully that would keep the tilt piston from hitting. With your explanation of pitch/revs, it would seem I would need to drop to a 9 pitch 4 blade prop at best, and an 8 at worst.
I also need to clean the lime off of the pontoons, that cant be helping. Good advice delivered in an excellent manner. Thank you again!

[OldMech]

That looks like the AV large gear case version of the DF50. That explains the prop pitch.

Can you elaborate? Thanks!

[mrpister]

Can you elaborate? Thanks!

I was confused when you said your 50 came with an 11 pitch. I thought it was too small. Then I realized you have the high thrust version AV.

According to my memory, the 50 makes maximum HP at 5800 rpm, so I would definitely drop your pitch as suggested.

[OldMech]

Ahh, ok, thank you!!!

raised the engine up and had a look at it last night, and I think the solution is simple enough,, Build a new knuckle... The knuckle the pin goes through to connect the engine to the hydraulic trim cylinder. On my version it will still thread onto the cylinder ram, but it will not have a top. Remove the top of the knuckle so the engine can kick up and away, but I will install a piece of spring steel that the pin will have to snap over/past so that I can still reverse to a limited extent. I will have to tinker with the tension of the clip... this way I can still use the trim, but have the safety of release... why doesnt this come standard from the factory?

[OldMech]

Made the new piece today, and it seems to work as hoped, still need to make the clip that will snap over the pin. STILL, not sure why something like this is not standard equipment... Another idea is to make a secondary transom that is hinged. I could use an electric solenoid to activate a pin that would engage and keep the motor from coming up in reverse... That would have to be a rugged unit though, not sure if the weight would be prohibitive.

[OldMech]

Update!

I have had the toon on the river about 6 times now. Had no issues with hitting anything until the last run. River was low, but wife wanted to go, so off we went... All was good until we came back down river headed for the ramp... caught a log... engine went UP and over and off we went... new stainless prop looks good but scuffed a little paint. I am SO VERY happy with the piece I machined. If this is the only log I ever hit, it was worth the time and effort. If not for that notched lift knuckle I am sure I would be fixing boat, or motor, or both. Trim still works perfectly so i have really lost nothing but the time to make the piece.
Thanks for the input and replies! Happy boating!