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badfisherman

any reliable way to get more power from a volvo penta

8 posts in this topic

I have a 94 crestliner 1750 sportfish with a volvo penta 2.3 litre. It tops out just over 35 mph. does anyone know of a way to get more power out of it? I have been looking online and I can't find any info anywhere. Any help would be appreciated.

Thanks

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just like you would with any car engine. Upgrade the ignition system, fuel system, intake, and exhaust. You should see power gains with each uprade. Now the hard part is that its a volvo, thats going to make finding the parts hard, but if you look hard enough im sure you can find something

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Thanks for the advice. I've searched all over the internet for performance upgrades but I cant find anything. I was thinking a bigger carb would help alot. The stock one that is on there is tiny.

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Being trimmed right then onto being propped right is the cheapest move. If your running with your throttle to the firewall then your not in the right mind for a I/O.

IMO, I/Os are meant to run at a good cruising speed.

That would be running the RPMs at around 3000 RPMs. That isn't at WOT btw. It means enough power to get you up on plane then back off the throttle to 3000. I would never run I/O at WOT maxing out the RPMs, outboard yes, I/O no.

So, lets say you want more speed out of the I/O I would first ask how is the hole shot and what are the RPMS at WOT.

It is possible to take some of the hole shot off but gain speed while keeping a good cruising RPM by changing the prop.

Something have to give though and it'll be the trottel pushed closer to the firewall. That will be less MPG. Then again there is a threshold where your not cruising any longer, instead your lugging the engine. Equate that to putting your car on cruise control and coming to a hill, except in this case your boat won't up shift like the car, instead it;;l bog and be sluggish. Again a comparison of I/O and car engine is, your hiway speeds are around 2500-3000 rpm. How long do your think an I/O would last at constant cruising speeds above that?

Sure you could go faster in the car, but do your think the engine would last longer keeping it under 3000 RPMs as opposed to being red lined? Of coarse it would.

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I am no I/O expert at all, but I can say that getting the right Stainless Steel prop will help you out. Not sure what the volvo can use, but I bet there is a Merc hub that will fit it for Merc props.

If you want hole shot and slower planing speed, and better "handling" then try a Hi-5. (reverse ins't as good with Hi-5, so be more careful around docks) If you want more speed then a Tempest. I am sure there are others that are good, but those two are great choices, IMO.

Good luck.

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I don't think that there is much left to squeeze out of his setup. The 4 cyl I/O's are the entry level I/O setups. I am actually impressed with the 35 for speed. My TYEE only does 39 GPS at 5800 with a 175 two stroke. If it is dependable leave it alone! If you have a need for speed buy a go-fast boat.

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Thanks for all the info guys. I just got the boat and was a little let down with the top end speed. Obviosly I am not going to cruise around with it wide open. I want the thing to last. But on the other hand I'd like to be able to cruise at 30 mph without reving the heck out of the engine. It does jump out of the hole pretty quick so maybe a different prop would make it cruise a little faster without reving the engine so high. I still want to be able to pull a tube and maybe a skiier too. The prop thats on it only lets the boat rev to 4700 RPMs witch is probably a good thing cause the max operating RPM is 5000.

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I am no I/O expert at all, but I can say that getting the right Stainless Steel prop will help you out. Not sure what the volvo can use, but I bet there is a Merc hub that will fit it for Merc props.

If you want hole shot and slower planing speed, and better "handling" then try a Hi-5. (reverse ins't as good with Hi-5, so be more careful around docks) If you want more speed then a Tempest. I am sure there are others that are good, but those two are great choices, IMO.

Good luck.

I just put a hi-5 on my 21" glass boat (150 yam 4S) and really like it. It "jumps" out of the water and gets on plane in honestly less than 2 seconds. I get the same top speed as my 3 blade (but at higher rpms) and the handeling in amazing. But boxman is right about reverse, it is like a blender in the water. bad for quick dock corrections but great for backtrolling.

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