Changing engines on a GW Gulfstream

[Roarque]

I have a 2006 Gulfstream and the twin F150s are getting up there in hours. I want to replace them with engines that have better fuel economy. I plan to replace the two 150s with one F350 AND two F9.9 high thrust kickers. Why? Because I spend half my time trolling for salmon and because my slip in the marina is a tight fit. Today, I use my twin 150s to maneuver into and out of the marina. That's why I want the twin kickers. I'll straddle the big engine with the kickers - one to port and one to starboard. I think with the high thrust props on the F9.9's I should be able to spin the hull in its length.

So I'll start up the two kickers to get out of harbour and then start up the big engine, shut off the twins and go fast to the fishing grounds. Then, I'll use one of the kickers to troll with downriggers.

The big issue is (a) will the 9.9s move the hull well in tight quarters - I may decide to go to 25 HP HT kickers and (b) how to set up the helm controls to operate in two different power configurations.

I love to hear any comments about how this set-up has worked elsewhere - if it has ever been done. While it seems like the second kicker is redundant, these little guys aren't that expensive. And they can be maintained for a lot less money than F150s.

 

[1998sailfish]

Isn't a bow thruster installation much cheaper to install and less complicated to rig ? I'm assuming that you still need a 9.9 for slow trolling.

 

[GulfSea]

This is really thinking outside the box. I think it's a great idea and probably a first of it's kind! Keep us posted as you progress.

 

[bayrat]

I have a 2006 Gulfstream and the twin F150s are getting up there in hours. I want to replace them with engines that have better fuel economy. I plan to replace the two 150s with one F350 AND two F9.9 high thrust kickers. Why? Because I spend half my time trolling for salmon and because my slip in the marina is a tight fit. Today, I use my twin 150s to maneuver into and out of the marina. That's why I want the twin kickers. I'll straddle the big engine with the kickers - one to port and one to starboard. I think with the high thrust props on the F9.9's I should be able to spin the hull in its length.

So I'll start up the two kickers to get out of harbour and then start up the big engine, shut off the twins and go fast to the fishing grounds. Then, I'll use one of the kickers to troll with downriggers.

The big issue is (a) will the 9.9s move the hull well in tight quarters - I may decide to go to 25 HP HT kickers and (b) how to set up the helm controls to operate in two different power configurations.

I love to hear any comments about how this set-up has worked elsewhere - if it has ever been done. While it seems like the second kicker is redundant, these little guys aren't that expensive. And they can be maintained for a lot less money than F150s.

How many hours on the F 150's? Do they run well? I think a new f350 is 25k -30k..not installed, and they have had some issues (flywheel , water ingestion etc). You cant just troll with one f 150 running and one shut down? It seems to me that you are looking to complicate your boating experience a bit, including cost...but thats just me. Good luck

 

[HMBJack]

Nice to ponder this innovative idea but I personally would add a bow thruster and be done with it.

Just the control cables/throttles/steering/trim alone for a twin kicker set-up will cost you about what a bow thruster would cost. And I'd much rather have 2 F150's than a single F350 since if one engine fails, the other will get you home (less certain of the kickers on a windy, rough day).

I think you would add value if you added a bow thruster to your boat. Spending all your money on your configuration will likely result in money lost but that's just my opinion. No Gulf Stream ever had 3 engines to my knowledge.

 

[ocnslr]

I have a 2006 Gulfstream and the twin F150s are getting up there in hours. I want to replace them with engines that have better fuel economy.

We repowered from the original 250HP OX66 to twin F150s in Oct 2005. We have almost 1400 hours on the F150s and they run great.

How many hours do you consider "up there"?

Brian

 

[JJRJR]

I agree. Twins all the way. I have 1992 Johnson 150's with closer to 1,500 hours each and they purr like a kitten. They are thirsty, but they fire right up and run strong. Still have over 100 psi compression in all 12 cylinders.

 

[suzukidave]

i can't imagine tilting down two kickers and starting them up every time i want to dock the boat. not sure how you would rig the steering either.

if you really want a single big motor with the manoueverability of twins i think you could do it with a single kicker and the main with some practice on the throttle.

can you not get a better slip?

 

[mdscole]

I'm not sure the math works out. I also have the OM66 twin 150 on a Voyager 248. The fuel economy is truly horrible. On flat water at optimum cruise, I can't get more than 1.7 mpg. (Yamaha - made in Saudi Arabia)

BUT

Spending $30,000 + 2 kickers + install, so the MPG goes from 1.7 to 2.5 is ridiculous. The safety of the twins, the unbelievable maneuverability - with reverse thrust on one... It just doesn't make a lot of sense. I did add a 4 stroke 9.9 (just one) to my crowded transom for trolling purposes - and that has really worked out great. The stink, vibration, speed issue, etc...all gone. Not to mention the 9.9 will burn a gallon of gas all day.

This is not the cheapest hobby one can engage in...