34’ diesel Amberjack,what needs to be done to engines for spring commissioning

R

RGboatman

New Member
Mar 3, 2005
23
Northshore Boston,Ma.
Boat Info
2001 340 Amberjack Principal Interest
Engines
Twin 3126 diesels
First spring with new to me 34’ diesel Amberjack. What needs to be done to engines before splashing boat? All oils and filters changed, engine zincs done. Changed impellers.
 
Check & tighten/replace as needed all hose clamps and critical connections will have 2 clamps... Belts ? Anti-Freeze ? Clean air filters ? Load test battteries ? Clean all raw water strainer baskets ? Degrease bilge and repaint ?
 
Welcome!! There is a great group here with lots of CAT 3116/3126 knowledge.

Heat exchangers, after coolers. When where they serviced last?

The Cat engines are very DIY. Almost everything readily available at www.parts.cat.com
 
Last edited:
RGboatman said:
First spring with new to me 34’ diesel Amberjack. What needs to be done to engines before splashing boat? All oils and filters changed, engine zincs done. Changed impellers.
Click to expand...

side note - that boat must fly (and get damn good mileage while at it) I didn't realize the 340 AJ came in diesel.

post some pictures!
 
Hey y'all. I am a new member here looking to gain knowledge from you seasoned pros! :)

I hope I can get some feedback/opinions/experience on a boat I'm ready to make an offer on. I am upgrading to a 2001 SeaRay Amberjack 340 with twin CAT 3126 with 300hp. Most of these models have the gas Mercruiser. I found and am leaning towards one with diesels (at a considerably higher price). I made offer yesterday and want to be sure I am making the best choice.

ANY input is appreciated. The engines currently have about 1350 hours. Seems like low hours for a 22 year old diesel. Anyway, performance, mileage, dependability, maintenance...you name it I welcome the info about it.

I am going from a 22ft on a lake to a 34ft on the Gulf so I am open to any advice...or warnings!

Thanks in advance !!!!
 
SShepp said:
Hey y'all. I am a new member here looking to gain knowledge from you seasoned pros! :)

I hope I can get some feedback/opinions/experience on a boat I'm ready to make an offer on. I am upgrading to a 2001 SeaRay Amberjack 340 with twin CAT 3126 with 300hp. Most of these models have the gas Mercruiser. I found and am leaning towards one with diesels (at a considerably higher price). I made offer yesterday and want to be sure I am making the best choice.

ANY input is appreciated. The engines currently have about 1350 hours. Seems like low hours for a 22 year old diesel. Anyway, performance, mileage, dependability, maintenance...you name it I welcome the info about it.

I am going from a 22ft on a lake to a 34ft on the Gulf so I am open to any advice...or warnings!

Thanks in advance !!!!
Click to expand...

My two cents...I don't think it makes sense to buy a diesel 340. A 340 doesn't need diesels to perform perfectly. And man alive...working in a gas powered 340 engine room is pure pain, truly. I can't imagine what the diesel is going to look like. I hope you have some small friends. That said, AJ's aren't as widely available as the Sundancer so if this is a slick boat, you might not have a lot of options to compare.

Upside - you'll burn a bit less gas and you can leave your generator running all night long. And...you can hang with the diesel crowds around the docks, they can be quite exclusive :) For reference I run around .65-.7MPG in my boat with gas, the diesel guys can get 1.0mpg, sometimes a bit higher I think. Do the math on how much you think you'll use the boat (50 hours a year is pretty typical if you're in a cooler climate) and see what you'll save on fuel. If you DIY maintenance there shouldn't be a massive difference. A few gallons of oil is what mostly separates us.

You should be able to sell the boat for a higher price when the time comes but you'll have a much smaller target buying group. I don't speak for us all but when I was shopping for a 330/340 I was coming from a 240, similar to you, and the last thing I wanted to think about was dealing with diesels. The move up in size was enough to keep me up at night.

Good luck! For what it's worth my next boat will be a diesel, for sure. But for a 340...in the USA...where you can get gas everywhere? Nah...
 
Thank you @Stee6043 for the feedback. I don't know if overall usage/hours make a difference in the "economy" of the gas vs. diesel engines. I do however, hope to using the boat quite a bit for coastal cruising along the Southern and Florida gulf coast. So, I would anticipate up to several hundred hours a year. That's what I hope anyway!

I read that the diesel with direct drive has a huge engine room to work in. The gas (I guess all of them??) I think are aft with v-drives. I read (don't know first hand) that that setup is much easier and friendly to service and less likely to cause problem with transmission, etc. Does that make sense?
 
SShepp said:
Thank you @Stee6043 for the feedback. I don't know if overall usage/hours make a difference in the "economy" of the gas vs. diesel engines. I do however, hope to using the boat quite a bit for coastal cruising along the Southern and Florida gulf coast. So, I would anticipate up to several hundred hours a year. That's what I hope anyway!

I read that the diesel with direct drive has a huge engine room to work in. The gas (I guess all of them??) I think are aft with v-drives. I read (don't know first hand) that that setup is much easier and friendly to service and less likely to cause problem with transmission, etc. Does that make sense?
Click to expand...
It's the Sundancer's that have the V-drives.
 
SShepp said:
Thank you @Stee6043 for the feedback. I don't know if overall usage/hours make a difference in the "economy" of the gas vs. diesel engines. I do however, hope to using the boat quite a bit for coastal cruising along the Southern and Florida gulf coast. So, I would anticipate up to several hundred hours a year. That's what I hope anyway!

I read that the diesel with direct drive has a huge engine room to work in. The gas (I guess all of them??) I think are aft with v-drives. I read (don't know first hand) that that setup is much easier and friendly to service and less likely to cause problem with transmission, etc. Does that make sense?
Click to expand...

I failed to recall the AJ has straight shafts like the express. That would definitely help with engine access (at the expense of the mid-berth the dancers have). The 330/340DA engine room is not for the faint of heart.

Overall use makes a difference in your ROI on the diesels. You're going to pay a premium for diesels and the only real benefit (in my opinion) in a boat this size will be fuel economy. With 0.4-0.5mpg edge on gas power, you have to burn a whole lotta fuel to make up for the $20-30k premium the diesel typically gets. That's all I'm trying to suggest.
 
Perhaps this is already in your plan, but make sure you get a motor survey along with the hull survey on this boat. One new turbo costs the same as a reman 7.4L! :)
 
Good advice, yes I will be getting a vessel and mechanical survey.

So let me ask, you stated, "For reference I run around .65-.7MPG in my boat with gas, the diesel guys can get 1.0mpg". Is that "cruising" speed at 2500ish rpms? I read in another forum that at lower rpm (I am in no rush to get anywhere) economy gets better on the diesel. It was stated that on those CATS @ 1450 RPM burn rate would be about 3gph, but I don't know what speed that would equate to. From a basic perspective, if 1400 rpms burning 3gph can get me 9-10 mph, I think I'm fine with that in many cases. And of course, it's good to have the power when you need to throw the throttle down.
 
seller stated this, could it really be possible?

• We had new props put on in 2022. This increased the fuel mileage to around 1.5 to 2 miles per gallon at 20 to 25 knots. We usually cruise at 1,900 to 2,200 RPMS.
 
SShepp said:
Good advice, yes I will be getting a vessel and mechanical survey.

So let me ask, you stated, "For reference I run around .65-.7MPG in my boat with gas, the diesel guys can get 1.0mpg". Is that "cruising" speed at 2500ish rpms? I read in another forum that at lower rpm (I am in no rush to get anywhere) economy gets better on the diesel. It was stated that on those CATS @ 1450 RPM burn rate would be about 3gph, but I don't know what speed that would equate to. From a basic perspective, if 1400 rpms burning 3gph can get me 9-10 mph, I think I'm fine with that in many cases. And of course, it's good to have the power when you need to throw the throttle down.
Click to expand...

That bolded mileage at cruise would be at very different RPM's for gas and diesel. I can get 1.0mpg if I want to run 15kts. Shoot, at 7-8kts I'm probably running 20MPG :) I cruise closer to 3600 rpm with gas @ 22-23kts. Diesels will be quite a lot lower RPM for the same speed.

Below is what 0.69MPG (statute) looks like on my 400 with gas. Going slower will increase economy...but I'm not that patient and my motors really like to be in the 3400-3600 range...they just sound right.

53116472560_d03b0a8468_h.jpg
 
SShepp said:
seller stated this, could it really be possible?

• We had new props put on in 2022. This increased the fuel mileage to around 1.5 to 2 miles per gallon at 20 to 25 knots. We usually cruise at 1,900 to 2,200 RPMS.
Click to expand...

25kts at 12-16gph sounds like a stretch to me...but I've never owned a diesel. You might want to pop over to the 340 specific thread and see what those guys (with gas) are running. I doubt you'll find many/any with diesel but it's worth a shot. The smallest diesel I've heard of around these parts is a 370, maybe a 360, but they are very few and far between.
 
Here's what 0.76mpg looks like at a screaming fast 29mph. This would be when fuel is closer to 1/2 tank, maybe 1/2 water, no waves. I don't run like this. I was just doing it when I first got my Fox gateways...

52897151879_3b6507c30f_h.jpg
 
SShepp said:
seller stated this, could it really be possible?

• We had new props put on in 2022. This increased the fuel mileage to around 1.5 to 2 miles per gallon at 20 to 25 knots. We usually cruise at 1,900 to 2,200 RPMS.
Click to expand...

This is the consumption chart for the 350hp 3126, I’m sure one exists for the 300HP version and I’d expect the consumption to be slightly less. If those boat speed numbers are correct, I could see that 340 getting 1.5+ all day long.

As far as the purchase goes - get CAT to do a full engine survey including exhaust temp and turbo boost check. You should also have them send out all fluid samples for analysis. Ask the owner when the last time the raw water system was serviced and make sure they comment whether the aftercoolers were removed, cleaned, and tested.

Make sure to run the boat up to WOT for a period of time (a couple minutes at least) and ensure it reaches 2800RPM minimum, preferably 2850. If they propped it for higher speed at 1900-2200 it might be overpropped, but the wot test will tell you that.

They are fantastic engines if you get a green light from the survey.

IMG_4998.jpeg
 
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