sailfish I\O twin ,or single?

[NjRichie]

Hello all, new to the Forum here and new to Gradys. Just bought my first Grady and love it! 87 seafarer 200yam outboard...Not originaly wanting an outboard ( im a auto tech by trade, and know the tradiatonal 4 stroke alot better) Its just like my jet ski engines just a few more cylinders. but any way i landed a good deal and the rest was history.
** my question is for you I\O Guys in your Sailfish, I see that some of them came with a single v-8 5.7, or a twin 4 cylinder. How Much different is the single i\o vs the twin? would the 2 160hps 4clys equal to the single 300-ish hp v-8 or am i just thinking too easily?
Im not looking for one just yet, but winter will be here soon enough and if i have some extra time i will be "looking" for the next boat for the growing family, plus i like the idea of having swim platform to transport the stand up jet ski on..
Thanks all
Rich

 

[JeffN]

My '83 had twin 170 HP 4cyl. Mercruisers until two years ago. I replaced with a single 496 that if memory serves puts out 375 HP. I am very pleased with the swap. The twins were very good on fuel but I find the single 496 to be very similar in performance and fuel consumption, actually the 496 is probably better on both counts. I feel the single 496 is lighter than the twins even though they were aluminum blocks. Back in the 90s when Mercruiser discontinued the 470s I inquired at Grady about what they would reccomend for a repower on my hull. At the time they were producing the Sailfish with twin V-6, the 350, and the 454. The gentleman I spoke with at Grady said the 350 was kind of doggy and would be better off with the 454. I think the 300 HP you mentioned might be a little light on power. You might look into the twin V-6 there were a lot of them in my area back then. To make them fit in my '83 when I repoweredI was looking at a lot of glass work on the motor box and deck. In the end I am very happy with the single.

 

[UpGrady]

I am running an 86' Sailfish with twin 470's and worked charters on lake O on a 25' 1983 Trophy with a single 454. I beleive that the Con's of the single engine outweigh the con's for the twins a boat this size.

#1- this is a very heavy boat to be pushing with a single outdrive, you are likely begging for outdrive issues down the road. (I am a bit skewed here as the Trophy was running an OMC which stunk to begin with, but... this is still a viable arguement against).... not one outdrive issue with my twins...

#2- The single screw was very ugly in a following sea, not enough thrust to push thru and not enough control at the stern to stay straight. I can run a solid 3500 rpm thru 5' following seas with my twins and never miss a beat on Lake O.

 

[JeffN]

I boat in southern New England and I have never noticed the following sea problem with mine.

You do bring up a good point about the OMCs. I would stay away from both the original OMC and the later Cobra versions they came and went pretty fast. Also bear in mind that the 470s have been out of production almost 20 years, the big V-8s MAY be easier to get parts for. The 470s had many idiosyncracies and in over 20 years of ownership I dealt with most of them. I just tired of throwing money at them. My drives were never a problem either I would have them gone through every couple of years. Not expensive and no failures. I would have preferred twins but money was a factor when it came to repower. If I were buying used and I was sure that the new model V-6 would fit in place of original V-6 Mercruisers I would look for one of those models. There were far more of those in my area than either single. I would have repowered with the V-6 in a heartbeat had they not been so problematic to fit. There were many 470 and 488 boats in my area and for their time they were a great power package. I will say that every time I shift the new motor I get a great big smile. The shifting on the 470 was odd at best.

 

[Amigo]

I have an 1988 25 ft. sailfish with a 454 CI, 330 HP pushing through a Bravo drive. I fish Lake Michigan and use a kicker OB for trolling.

She gets out of the hole fast enough for me. I'm somewhat underproped which helps in that area. I cruise at 22 - 23 MPH at 3,200RPM for about 12 gallons per hour reading from a FloScan.

The one thing I did notice was the heat generated by the upper gear set. That part of the outdrive comes up our of the water on plane. Water that was occasionally splashing on the upper housing would immediately turn to steam. The vaporizing water was leaving a mineral buildup on the black paint.

I installed a water shower on the drive. The constant water shower does reduce the heat on the housing surface and I would believe internally as well. The drive oil has never shown to have been overheated.

The only outdrive repair mantenance was an upper oil seal leak about 4 years ago. No repair maintenance on the engine except a few tune ups.

 

[NjRichie]

thanks for the replys.
I did not know a twin v-6 was an option, are they all seperate models or was it the same boat with a different power plant? the same boat with 1 or 2 holes for drives? or is the engine area different in size?
how would i go about telling if the boat was originaly and twin or a single and may have been changed? The idea of having a single drive then switching to a double seems to be a lot of transom repair and if it was not done correctly would be asking for problems in the future
* i know like on Motor Vehicles, the VIN # can tell every thing about the vehicle... IE. year,make,engine,ect...
Thanks,
Rich

 

[Amigo]

The hatch width for my single 454 CI is 3 feet. The wo tstringers are also on three foot centers. A configuration for twins would need to be much different including stringers for mounting two engines.

 

[JeffN]

I'll measure my engine box. I think it depends on the year. Many years ago a local guy went from 488s to twinV-6 and had to do a lot of work to his deck and his engine box as the opening and box were too narrow. His boat was an '82 or older. I measured a latter model with V-6s at one point and that motor box and opening were the same width as mine. My motors were on 21 or 22 inch centers the V-6 were further apart. The problem I ran into with my repower was that current engines are wider, I think it is a change in the manifolds so I needed more width. I think that perhaps after '82 the hatch and opening were a standard size. IIRC all the Sailfish with I/Os were Sailfish 254. Prior to '84 the I/O was a Kingfish same hull and everything as a Sailfish. I don't know how you would tell what engines came in a particular boat at this point.

If you are curious about what was offered when you can go on the Grady site and look up sales literature from the years you are interested in.
I have a 1986 Grady price list that is interesting reading.