Tohatsu 3.5 Outboard Shearpin Question-xposted from Yahoo

[Gil Weiss]

I have a new 3.5 Tohatsu long shaft with forward and neutral shifting on my CP16. It has performed flawlessly all season. I only really use it for getting in and out of the marina so I am just into my second gallon of fuel for this season. Have about 5 hours run time on the motor so it is just broken in.

We went out sailing Sunday and all was well until I fired up the motor to get back into my slip. Shifted into neutral and nothing happened? We wound up paddling in and I check out the motor to find the original brass shear pin was sheared. We never hit anything, there was no sign of tangling or hitting anything so this seemed strange. I replaced the stock shear pin with a stainless steel pin the motor dealer provided as an additional spare.He mentioned the stock pins were soft. Walla, the motor worked fine! While using a stainless steel pin bothers me a bit, so does the idea of a too soft brass one that may break at a bad time. I figure the torque when shifting into gear must have weaked the pin? The engine idles very low so the torque is minimal.

Anyone have a similar experience or any comments?

[spaul]

Hi Gil, the very fact that your kind and thoughtful dealer gave you a stainless replacement must indicate experience with this as a problem. Remember the shear pin is there to protect the engine and drive train. Not necessarily the propeller but that is hoped. I've had similar problems with smaller outboards. sometimes a shear pin (which is bearing the drive load) just gives out. I wouldn't be worried about the stainless one. Of course it goes without saying the stainless one is harder and will shear at a much higher force. It should also not have as much "creep" and should last until you hit something.  :oops: Perish the thought.
Let us know how this continues to work for you. I also want to congratulate you on not dropping the stainless pin in the water which is what I would have done, and in front of onlookers as well.
Regards,
Steve Paul
cp27/2
" IM PAUL SIVE"

[Gil Weiss]

Hi Steve,

Thanks for the comments . . . By the time we got back into our slip it was almost dark and there were no onlookers. I actually took the motor off the boat and replaced the shear pin on the dock. You really cannot accomplish this with the motor on the boat unless you got into the water.

Anyway, our embarassment was in paddling by all the on lookers watching from a rockpile that juts out at the entrance of the marina. Normally we motor by in stately fashion looking like we just came in from another great day at sea. With no wind we had to resort to paddling by the onlookers . . .ugh.

I will say, however, that having paddling as a viable back up power source is another advantage of a CP16!

[spaul]

Hi Gil, You're right about that paddling thing. Having moved up to the cp27 we don't have backup propulsion. We spend our time on a closed lake for the most part If we were to take her (boat) to the Great Lakes or further East to the shore we'd have a dingy and outboard.
From a discussion with my first mate about the engine dying I suggested she could have two choices. Swim with a bowline or push from the swim ladder. I've since hired personal protection as I've heard she has a contract out on me.
Keep sailing, the year is getting short and we pull our boats towards the middle or end of October.
Regards,
Steve Paul
cp27/2
"IM PAUL SIVE"

[Gil Weiss]

You always need a back up plan. Sometimes it can be the anchor and a cell phone.

Last year I had a tohatsu 4stroke 4hp engine die on me as a major storm approched the lake. First time I got caught out in a lightening storm in 40 years of boating. I got a tow and we made it back unscathed, but I don't want to do that again.I traded that engine this past winter on the new 3.5 2 stroke.

We are taking off from work early tomorrow and going sailing as the time (and days) are getting short. Was hoping to getout Saturday too, but the wx forecast is going down hill . . .

[bro t]

Hi Gil,
I was out last Saturday and actually described to a friend how I could set up a sweep on the cp16:  with an oarlock (sidemount style) on the outside of the coamings, positioned so that the oarsman sits with back to the companionway, using oars about 10 or 12 feet long, might be a viable and perhaps even boat saving "anthropic wind" for when the iron wind fouls the proverbial bed.  In a good blow and having to go windward, the loss of motor can be most distressing.  I should add that it appears to be a good position for rowing, the rudder preferably lifted unless you have crew... I rowed crew in high school, and after paddling the 16, and rowing a variety of boats, I think the 16 would do quite well.  (Anyone tried it yet?).  A few years back we were in Penobscot Bay (Owl's Head, Maine), and had to either motor or not achieve our mooring, for it was impossible to tack through the dozens of craft (mostly lobsterboats) without doing damage, at the minimum, to my ego and self-esteem :oops: , let alone the boat.  Sometime I should write a full account of the comedy that day unveiled, but for brevity now, it suffices to say we were a major source of entertainment for two anchored schooners for nearly an hour with motor trouble, while we jigged, rigged, and dogged our way home.  If I'd broken a brass shear pin that day, I'd have blown a gasket, too!!!! :wink:
bro t. from Upwest Maine

[Craig]

Seems to me there was someone a while back who put oarlocks on a 16 and posted pictures on the Yahoo site.  I didn't check the files section but might be worth a look.

Craig

[Gil Weiss]

If you ever saw the life boats on the New Jersey beaches, you would notice a great similarity between their hull shape and the CP16. The life boats row very well (they are heavily built too).

But, my game is sailing, so I'll stick with sails, my 3.5 Tohatsu and paddles, in that order . . .

I snuck out of an off site meeting yesterday, picked up my wife and went sailing. It was a beautiful day but light on wind in the beginning. As the sun got lower a nice breeze came up and we had about an hour and a half of wonderful conditions. Sailed back to the marina with the nav lights on. We basically had the whole lake to ourselves which was nice too. Stopped at a nice restuarant for dinner and I forgot I even went to work early yesterday. Another fine time on our CP16 as the season nears its end.

[Bruce Woods]

anyone have pictures of these shear pins, and how to replace them? I have been lucky so far (knock on my head, as it is like wood)....

I have a canoe paddle I have used. Works well from bow if I have someone on the rudder...if not, I paddle from cockpit...

[Gil Weiss]

The Tohatsu 3.5 shear pin is 5/32" thick and an inch long. It goes through the propellor drive shaft and rides in a cavity at the rear of the prop.  It shears if you hit something or otherwise impede the prop from turning to protech the drivetrain. To get to it all you need do is remove the large split pint going through the propellor hub and pull off the prop.

[wmswart]

Gil et. al.  My kids like to "fish" by dragging long lengths of 1/4" line off the boat.  One of my worst fears came true this weekend ... I wound the line around the prop so bad I had to take the prop off to get the line out!  Long story, but we were out in pretty strong winds and had to have a friend tow us to a lee shoreline to remedy the problem.  I was surprised I didn't shear the pin when I engaged the motor into forward, but discovered when I removed the prop that the previous owner of my boat/motor had used a hardened bolt for a shear pin.  Should the pin have sheared off when the line wrapped around the prop??

[Gil Weiss]

Hi Bill,

In theory the shear pin should have broken from the line tangle. However, in reality, it doesn't always happen. If the line tangle it pulls up slowly the  motor stalls out first. You were lucky that you could get the tow to shallow and calmer waters.

I have always seen shear pins as a 50/50 thing. If they break too easily you can get into trouble and if they don't break your engine gets damaged. My previous 4 hp 4 stroke Tothasu used some sort of rubber slipping mechanism rather than a pin. My concern with this was that what do you do if, from lots of use, it starts to slip permanently? I never kept the engine long enough to find out.

Luckily I am in deep water and I don't use the engine much. But, I consider the engine a valuable saftey item if the weather starts to get nasty. I hjad a very bad experience last year when the 4hp Tohatsu died while I was trying to get in to dock from a severe thunderstorm.

[montrosesail]

I sail a CP16 on Lake Michigan w/ a 3.5hp Tohatsu. The shear pin on that motor is rather troublesome.  I've only managed to go one season in four without shearing it at least once. I've never had a fouled prop and always use the motor in/out of the harbor.

The pin will shear if I have any forward momentum when I start the motor and take it out of netural.  I found the key to preventing a shear when heading back in, is to take down all the sails and wait for the boat to slow nearly to a halt. Start the motor, keep the engine coughing with the throttle and choke, then shift into forward being careful to increase the throttle enough that the motor won't quit.

Hope this helps and happy sailing!

Jim

[Pat McL]

We have owned a 2.5hp British Seagull 2 stroke on our cp-16 since 1977. The shear pin on these outboards is a heavy spring which acts as a shock absorber rather than splitting immediately. Might check these out at http://www.saving-old-seagulls.co.uk/   -- Older technology, but works better than a straight pin. These Seagulls put out tremendous torque at low rpm and were designed primarily for displacement sailboats. --Pat & Suzy

[Craig Weis]

I agree with those who vote that the sheer pin being brass is no good.

The pins is only supose to protect the shaft and gears driving it. Not the prop.

So figure that the gears are hardened, the shaft bigger in dia than the pin, so fit the meanest, ugliest, fattest pin you can through the hole. Carry some spares, and a way to change the pin.

Ohhhhh, and slow the engine idle down to enhance the 'soft start or bite' that the prop has to make in the water.

The 'Moment of Bend' exceeds 'The moment of Torque' and all that 3.5hp [- what ever hp for low rpm] falls on the pin.

Learn to pause between Fwd. N. Rev. Let the prop stop before selecting a different rotation. Your on a boat. Not in a hurry.

My Com-Pac coming to the dock never slows down going into the slip. So I make her stop [sometime with rev] and then a chug-chug-chug-N. And drift in.

skip.