Repowering from twins to single and a kicker

[CDory23]

Hi all,

I just posted a thread about more issues I have with my twin yami 40s. I'm really sick of the carb issues and looking into repowering with new EFI so I can enjoy boating more and have less hassles. I just refuse to put anymore money into the carbs and instead put it towards a repower.

On my 22, I would really prefer to have a single power plant and a kicker for several reasons.

So my question is has anybody done this? Is there difficulties or issues that would make this an unpractical decision? I have a seastar power steering system that looks like it may need to be modified. Also I don't like the idea of 4 thru hulls being epoxied, but I don't see it being a big issue besides aesthetics.

Thanks.

[CDory23]

I know 1 thing right off is I would need to invest in trim tabs. The permatrims on my twins were fine, but I imagine thats a must for a single powerplant.

[Robert H. Wilkinson]

CDory23, the biggest problem I foresee with your plan is finding a stick big enough to defend yourself with when Harvey reads this!

[T.R. Bauer]

This can't be done - ever. You must buy a new boat. But in all seriously, if that is what you want, it is a simple conversion. You know you can finish epoxy and make things look nice, right?

[CDory23]

Haha. I'd really like to keep this thread focused on the potential issues of changeover to a single, but I don't mind stating some of my reasons.

1. More power to weight ratio hanging off the transom even with added weight of a kicker.
2. Less maintenance costs and my own time lost since I do my own maintenance.
3. Less hours on main motor. I do a lot of trolling and a kicker IMO is a better way to troll and keep hours low. I currently split hours by using one engine at a time.
4. I've had to come in with only one engine a couple times and I averaged about 8mph (ocean) with one 40. I don't think a high thrust kicker propped right would be too much slower than that. Twins are propped to be twins so using one in an emergency situation doesn't give you half the power in less you want to stop and change the prop out. So also for this reason I don't feel like you have any better backup with twins v.s. a main with a kicker.

These reasons are specifically for the 22 based off what my particular use of boat for and my experiences.

I'm not saying that twins aren't a better fit for other people or another boat. Twins do give you greater maneuverability and for me in the 22 eliminated the need for trim tabs.

Thanks

[CDory23]

Hi Bauer,

Yes I do know that. My thought process went from first having engine troubles and fixing to then pondering re-power and I just automatically thought to replace with what a I had which is twins. It seems like a very straight forward switch over but I didn't know if I was missing anything. Better safe than sorry. I also thought it would be nice to hear if anybody here on the forum has done this.

Thanks for the reply.

[Will-C]

Welcome to the other side.
D.D.

[hardee]

C-Dory23 said this:

[C-Hawk]

I went from twin 40s to a single 90 and kicker---- hated it!!!!
I am now back to twin 50 and loving it.
It may have just been the motor-- but I had nothing but trouble with it--- it had a serious drinking problem and would not give out any power.
With the twins I had a safe range of 150 miles-- with the 90 I might be able to go 100 miles if I had extra fuel on board.
With twins, you have two screws turning and that helps to keep you going straight at low speed-- with the single 90 I was having to drive the boat more.

[Sunbeam]

When I was first C-Dory shopping, I wanted a boat with twins. Not for any "real" reason, but just because I like the symmetry and think they look cool. Of course, that's all the reason one needs!

However, every boat I could find with twins was "wrong" in some other way (poor condition, color I don't like, high top when I wanted low top, etc.) The pristine ones that had all the other features I wanted all had single/kicker setups. I found one that was so just right (for me) that I decided to buy it, and immediately mentally dedicated the "extra" money for a re-power to twins.

I never found any stoppers if that's what I decided to do. Here are some of the considerations I found:

1) On some of the boats with twins, they moved the splashwell drain to the center (otherwise apparently one of the twin brackets covered it). If that was done on your boat, you'd want to re-establish the usual drain. You can tell where the "normal" one is because the splashwell molding has a sort of trough there (it's starboard of center).

2) As you mentioned, the engine mount holes would need to be closed and new ones made. To me, this isn't much of a negative, because I re-did mine anyway due to lack of the core being protected. This would be a great chance to fill the twin holes solidly and protect the core on the new holes.

3) You'd perhaps be removing one "control" at the helm (depending on how deluxe your kicker is); and likely you'd be going with a different/newer one. This might give you more room next to the helm seat.

4) You'll have an extra gauge hole at the helm, but they make various things that fit that size hole (even little stereos); or you can make a "cover plate" for the whole helm gauge area and then just cut holes where you want them (thin wood, starboard, other plastic, etc.). If you go Yamaha again, they have a second (same size) gauge you can get that shows more things (unless you already have that setup and thus have four gauge holes...).

5) You'll likely gain some space by removing a battery (presuming you have two start batteries?) and perhaps a fuel filter (I ran original kicker off same filter/tanks as main, with a quick release fitting so it could also go right to auxiliary tank).

6) You'll want to consider which side to put the kicker on. Each side seems to have plusses and minuses. Mine came to starboard, which I prefer. The good is that then the/a swim platform is to port, and you don't have to clamber over all the rigging wires/fuel lines. Also the tiller handle (if you have one) is clear of the splashwell side). On the other hand, it's more weight to starboard, which may be an issue if you don't have a passenger, have a lot of weight to starboard, etc. If the kicker is on port it's the opposite set of pros/cons.

As for me, after a season or two with the single main/kicker, I decided not to change to twins. I still think they look much better (lower, more symmetrical, don't come forward as far when tilted, and just cool), but found things I preferred with the setup I have that I don't want to give up. So now if/when I re-power, it will most likely be to a single again. Here were my "discoveries":

1) I found that I use the swim platform (and the open area of the splashwell leading to it) ALL the time on places like Powell. When beaching (I like to anchor the bow out and go in stern-to), when setting a stern anchor (I do it from the swim platform plus a small "bridge" platform I made that goes across the splashwell). Also (not beaching-specific) it's where I board the dinghy/kayak. You can fit a small swim platform with twins, but I now wouldn't want to give up the "big" one that I have with the single/kicker.

2) Although there are "problem" situations that favor either setup (and who knows which one you will encounter), I found that I feel comfortable with one engine (and its prop) up and out of the water, especially when I'm running on plane. I would have to take the time to lower it, and then I don't have mine set up for remote steering and throttle as a twin would be, but to my mind neither way is perfect, so it's just a matter of choosing.

3) I spent some time on similar boats with twins, and although maybe it's just me, I found that I "had" to have them perfectly synchronized or it would drive me nuts (I could hear a slight "hunting" otherwise). So I was often fiddling with the controls. I think it might be distracting for me in the long run (although I never did spend more than a couple of hours out cruising on a boat with twins). This may not be noticeable to others.

4) Side bonus, but it would be less expensive to re-power with a single vs. twins (but I'd pay the extra anyway if that's what I really wanted; however, see above reasons).

I don't fish (yet?) so those considerations weren't on my mind. I still think twins are cooler though, and they definitely also have plusses. I was just listing above why I ended up liking my single.

PS: Has someone gone to Hardee's house to check on him yet? Maybe bring some smelling salts...

[CDory23]

Well, the actual mechanics involved in switching from twins to a single seem to be a very easy concept so I will respond to others notes on why I'm considering.

Hardee wrote

[No offense, but the issue with the cooling system hose was not the twins fault, and it could have happened to either a single or the twins.]

No offense taken, it was 100% completely my fault that I left the flushing connectors unsecured while underway. Still the point remains that this does not seem to have anything to do with the issues I"m having in less there is some relation to that having a carb issue. It was purely quincidence. I'm still figuring it out will post back back with more info when I have it.

Hardee also wrote

[Really, you have to do what you have to do. If you do the switch, you are giving up some headaches, sure, like needing to know which handle to put in forward and which one to put into reverse when turning to or from the dock, or which side to raise and shut off when pocking around in really shallow water, just in case. ]

I'm not sure if that was sarcasm so I will respond to it as its not. To me that is not a headache but yet a positive aspect about the twins. More control, options, redundancy. I realize I would be giving it up.

As far as redundancy goes I posted that I averaged about 8mph in ocean conditions on 1 yami 40.

Does anybody here with a 22 have a top end speed to give on a high thrust 9.9 kicker?

You asked how many hours are on these Yami 40's. There is only 750! IMO very low and no way would I want to change these out if it weren't for more carb issues. (Still diagnosing as I said, but I do not want to put anymore money into these carbs) I keep fresh gas in (3 months or less) and run them on earmuffs on the trailer if boat is not ran at least every 2 weeks.

C-Hawk stated that his gas consumption went down when he switched to a single 90. That is very interesting and surprising to me. If I do switch it will be to a115. I feel that the twin yami 40's are under powered, I find myself at full throttle often. I feel sometimes the case is that a larger engine running at a lower rpm can often get better mileage than a smaller engine or engines being pushed hard and it is also better on the engine itself.

Lastly, If I did re-power with twins it would be 50's. I did some weight comparison and new 2016 Merc 115 with a 9.9 high thrust kicker comes in at 52lbs less then two new 2016 merc 50's. I didn't calculate this for all the outboards but the power to weight ratio seems to a general theme. [/quote]

[anchorout]

I know this has been addressed before, but my life experience is that if you disconnect the gas hose and run the engines until they die, running them completely out of gas, you will eliminate carb problems. With my 6hp kicker and 2.5hp dinghy motors, I also use the drain screws in the bottom of the carbs to drain every ounce of ethanol out. (I have found with real gas this is not necessary.) I have never had a problem with clogged jets, etc.

Didn't mean to sidetrack the discussion, but this might save you a re-power.

[C-Hawk]

I was very surprised at the lack of performance with my 90. There are several CD22's with the same setup that I had and they could run circles around. I do not have a lot of excess weight on the boat, but it would suck the fuel and go nowhere.
I took the area rep out and they ran diagnostics on the motor while running. They changed all of the sensors, but that didn't help.
I'm not dissing all of the 90s-- just the one that I had.
When I sold the 90 and went back to the twins, the mounting holes were plugged and gel coated over-- you don't even see where the 90 was mounted.

Roger
C-Hawk

[Rain]

CDory23, I have a 23 Venture with a 115 Suzuki main and a Suzuki 9.9 high thrust kicker like you asked about. I don't have the kicker broken in yet, so am not supposed to get it past 3000 RPM. Of course since I don't have a tach on the kicker, I don't know the RPMs and am just guessing anyway! That said, it pushes my boat, which is a little heavier than a 22', at a little over 4 NMPH at what I am guessing to be about 3000 RPM. I know I wouldn't want to take the boat through Deception Pass bucking both wind and current on the kicker! It would probably make it though if I could run it up to WOT. Hope that helps.

[localboy]

All modern vehicles use FI. For myriad reasons. Boats are no different.