Single Cylinder 4 stroke Outboard vibration

[Coednaked]

For those of you who own Single Cylinder 4 stroke outboards (i.e. Yamaha 2.5-4 HP and Honda 2-5 HP) I'm curious if you could relate your expieriences as far as vibration goes. I understand that single cylinder outboards will naturally not be as smooth running as their 2 cylinder and up counterparts. I am/was looking at getting a Yamaha F2.5 for a kicker on my 14 foot welded aluminumboat for back up power and for trolling (I have a Yamaha 20 HP 4 stroke as my main power) in saltwater and after going to the Yamaha dealer yesterday he said to really consider if it was worth buying or not as they have had the odd complaint about these things vibrating quite a lot, like vibrating the rod tips and things like that.

Thoughts, experience? I wouldn't be idling the engine right down. I'm guessing the right trolling speed for this motor would be in the 1500-4000 RPM range. I could use my main power as it does idle right down but I'd prefer to not put all those hours on my main power and it's nice to have back up power if anything ever happens.

 

[Silvertip]

Re: Single Cylinder 4 stroke Outboard vibration

In my view, you are wasting money. Your 20 HP will troll all day with no problem and as for the hours, you will not likely wear out this engine. You will have a new boat long before it wears out -- assuming proper maintenance of course. As for vibration, think lawn mower for comparison.

 

[Coednaked]

Re: Single Cylinder 4 stroke Outboard vibration

So initiate this comparison, any suggestions on how I rig my lawn mower to my transom?

Interestingly enough on a local fishing discussion board I frequent the first response I got completely contradicted yours and the person suggested I go with even a large Yamaha F4 or Honda 5 Horse (still both single cylinders). I guess he took the back up power idea to heart.

So you think I'm wasting my money even if it means having no back up power in the event something happens?

 

[ondarvr]

Re: Single Cylinder 4 stroke Outboard vibration

If you don't like vibration and noise, skip most any of the singles, they can be very irritating after just a few minutes especially on a small aluminum boat. For back up you can get one, but don't expect to like it for trolling. Most small singles are made to be light and low cost, not smooth and quiet.

 

[tashasdaddy]

Re: Single Cylinder 4 stroke Outboard vibration

single cylinder, equals vibrating chair syndrome.

 

[tommays]

Re: Single Cylinder 4 stroke Outboard vibration

I have a 4HP 2 stroke single which runs perfect in all ways. BUT puts a harmonic through the entire 24' sailboat at various RPM so i usally play around until i find and RPM that is a bit smooth


Now i have owned the exact same boat and motor mount with a 6HP 2 cylinder 2 stroke that you could only tell was running buy the sound

 

[TOHATSU GURU]

Re: Single Cylinder 4 stroke Outboard vibration

All single cylinder engines vibrate and all consumers complain about them...That's the nature of the little beasties.

 

[all thumbs]

Re: Single Cylinder 4 stroke Outboard vibration

Just got a yamaha 4hp 4 stroke this year for trolling. My problem was my main engine at idle was too fast, I got tired of putting out wind anchors to slow it down. Yes there is vibration and I can see the rod tips moving from it. But I can adjust the speed slower till it goes away. This usually puts me at around 1.5 mph. on a 16 ft. lund. I hooked it up to the water seperator that goes to the main engine ,a honda 4 stroke 50hp. Simple set up and it works as a back up if needed. Like others have said I've heard all single cylinders will vibrate.

 

[gss036]

Re: Single Cylinder 4 stroke Outboard vibration

I would agree that you need a back up for fishing saltwater. I would not go out w/o one. When some thing goes wrong, it is not like a car where you just drift over to the side of the road and call for help. On saltwater w/ the tide running, it like trying to sit still in the middle of a river running about 6 mph. I would suggest that you go up to the smallest 4 stroke which has twin cylinders and I think you will be pleased w/yourself for the choice.

 

[jay_merrill]

Re: Single Cylinder 4 stroke Outboard vibration

May I suggest a little less "tude" in regard to a perfectly legitimate response, given to you by a person who has offered much to this board and its members?

Single cylinder engines, no matter what they are attached to, tend to have vibration issues, hence the comparison to a lawnmowever. If you have ever held the handlebar of a single cylinder lawnmower, you will have some idea of what the characteristics of the outboard will be. The comparison is also a good one because the size of the motor (2.5 - 3.5 hp) is similar.

I also agree that having a trolling motor when your main powerplant is a 20hp motor isn't necessary. You should be able to idle the 20hp down to a suitable speed and the extra hours on the 20hp won't justify the added expense of the 2.5 hp over the expected life of eother one of them. Fuel use also wouldn't be a relevant issue because the 20hp will burn very little at idle.

I do agree with the philosophy that having a second motor for "get home" purposes, in the event of a failure of the main engine, is legitimate. If that is your primary concern, I would say go ahead and buy the smaller motor. The vibration will be a little bit annoying, but much less so than being stranded somewhere.

Once again, I don't know you and will assume that you are a nice person, but you aren't going to win any friends here by insulting a respected member of the forum. Something to think about.

 

[haskindm]

Re: Single Cylinder 4 stroke Outboard vibration

If your boat is small enough that your "main" power is 20-HP, a paddle or oar should be sufficient for backup power. I can't see that you could possibly save enough in fuel or engine wear to ever justify the cost of a kicker in this case. It makes sense when your main power is 200-300 HP, but in that case the "kicker" would proably 15 or 20 HP. In 25 years of boating and thousands of hours of operation, I have never needed backup power. Now if I was going 60-miles offshore, I would want the assurance of knowing that I had backup power, but in lakes and rivers, I don't believe that it is a real issue. The backup power on my 18' 115 HP Center Console is a paddle.