300 Suzuki repower on a 2520 DV notch transom

[Fishinfireman]

Well here is the update on my search for the best prop. I ran two Rev 4 props since my last post and I was disappointed in both of them. I ran a 17P and an 18P and neither one did as well as the Suzuki prop. The Rev 4s gave the boat a lot of bow lift until you got up into the higher speeds and then the bow came down and the stern seemed to lift. I could not trim the motor up very far with the 4 blades either.

All of the Merc props I have tried seem to run well with a light load but when I ran them with my typical charter load, the slip was pretty bad.

My last two trips were run with the 17P Suzuki prop and it works much better than the Merc props but it needs some adjustment to get me in the correct rpm range.

I fished today with a fairly heavy load (6 men including me and a full load of fuel) and we had the best sea we have had in a while. My best cruise #s were:

4600 rpm - 25kts - 14.9 gph - 1.67 nmpg - 1.92 mpg

I ran the boat with just me aboard this afternoon after my charter. I was carrying a big fish box with maybe 100# of ice and 115 gallons of fuel. Seas were smooth in the channel were I ran. Here are the #s :

4600 rpm - 28.4 kts - 14.7 gph - 1.93 nmpg - 2.22 mpg

5000 rpm - 31 kts - 18.3 gph - 1.69 nmpg - 1.94 mpg

5600 rpm(wot) - 34.6 kts - 23.9 gph - 1.44 nmpg - 1.66 mpg

I discussed my situation with a prop man who was highly recommended and I am going to let him adjust this prop as soon as I get another one to run.

One other thing I should mention is the dealer who sold me this motor put 20/50 oil in it and sold me 20/50 to do the 20 hour oil change. I have since found out that I should be running 10/40 oil. I don't know how much this will affect the way the motor runs but it may free it up some. We'll see. I now have about 70 hours on this motor and I am very impressed with it. It's a big improvement over my old OX66.

 

[John_Madison CT]

Very good work. Anything close to 2mpg with 6 guys and full fuel is very good.

How is it that Suzuki reports only about 8gph at 4000RPM's? That one would really confuse me. Have you asked other 300hp owners what they're finding at similar RPM's?

 

[Fishinfireman]

John, the fuel burn seems to drop about 1 gph per 100 rpm so if that holds true then the fuel burn at 4000 rpm would be right at 8 gph. I will try to check it at that speed my next trip.

I have not asked other owners about it but I think it all depends on how much weight the motor is pushing and the design of the hull. I think this motor would really shine on a 2520 MV.

 

[coastal]

Capt. Bill, thanks for the update on all your prop testing, I know it's a lot of work. It sounds like you have found a good motor/ prop combo for your boat, those numbers sound very good for a big deep vee that is fully loaded. I just received my rev 4 19p prop, and if family matters allow I hope to try it tomorrow, however after following all your hard work it sounds like my only decision will be between the suzuki 17p, and the 18.5p.

 

[Harpoon]

Do you get a squeel at idle rpms (sounds like alternator belt) ... I think I saw this comment on another thread. I haven't looked into doing anything about it yet. not a big deal, you only hear it because the motor is so quiet. I'm at like 185 hours......

 

[John_Madison CT]

FishinFireman: Just bumping up this thread. Curious how your fuel burn #'s are working out.

John

 

[Fishinfireman]

Harpoon, sorry I did not reply to your question. I didn't see it until John bumped the thread. To answer your question, yes I am starting to get a slight sqeal at idle, more of a whistle, but only after a long run. I have noticed it a couple of times when I get back to the dock at the end of the day. I have also noticed a fairly loud buzzing noise while running at cruise. It sounds like a Cicada. I believe it is one of the fuel pumps. It has not had any effect on the way the motor runs and I have not had any problems. I have an appointment for my 200 hr service on Aug 28 so I will let them know about the noises then. I love the motor. It is a beast and I work it hard.

John, I settled on the Suzuki prop but I had the 17 pitch taken down a little bit so my max rpm is now 5850. I am getting 1.3nmpg in tough seas and almost 1.8 nmpg in flat seas. In statute miles that is 1.5 - 2.0 mpg. I may have the prop taken down a little more to take more load off the engine but I wanted to run this one for a while first. I lost about 2 knots at cruise with the reduction in pitch but not as much off the top.

 

[B-Faithful]

FYI,

The DF 250 burns 10.5 gph @ 4000 and the 300 burns 7.85 GPH ?

I cannot speak on the Parker but I judt ahd to decide on a Honda 225 or a zuke 250 on a Judge and I was surprised to hear the fuel burn numbers on the zuke 250. I even spoke to an owner of a Judge 27 with a DF250 and he wished he had gone wiith the Honda due to fuel burn and a cabin "drone" at 4000rpms. (he has been on the boat with honda power as that is what his buddy went with).

I have been told that the Zuke 300 is more fuel efficient than the DF250. I am sure they are both reliable motors. I would have liked to consider the zuke 300 but it was like 3 grand more with dual station controlls and I didnt think the hp was needed for a mod v boat that does best crusing at 22-28mph.

Good thread on the 300zuke. it would be cool to hear of 300 verado repowers and etec 300 repowers on the deep v hull.