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loss of HP

when my hull and running gear were left uncleaned in california for 6 weeks, I was limited to 15knots and like 2450rpm on both engines
 
So by holding back on the boat say bottom build up will not only slow the speed/ Kts. But your RPM'S also drop by 1,000 or better
 
circle hook said:
So by holding back on the boat say bottom build up will not only slow the speed/ Kts. But your RPM'S also drop by 1,000 or better
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Yes. It's like an electric saw cutting through wood. The motor speed slows down significantly as you increase the resistance. You can even stall the motor completely if you try cutting through the wood too fast.

If your hull isn't moving fast enough through the water, the props won't be able to displace the water as efficiently. This increase in resistance on the props will limit your engine speed.

Thanks,
JJ
 
Great so the first thing I am going to do on day one in the water again try her at WOT and see what happens I didn't do that this last season so I never had a good base line before being in the water for a couple weeks. Thanks very much may be I was chase ing some thing that never was a machinal problem at all. Again thanks bob
 
Yea I M going for my scuba cert. this year and be able to do my oun also but I was so against the bottom condition I didn't think it was that bad but I ran out of reasons on what could cause this to both engines. I only bought the boat last year and had nothing to com pair the problem to so live & learn. Hay thanks and happy new year see you on the water. Spring is only around the corner.

Thanks bob
 
It's no fun getting old. Everything slows down a bit. You could be looking at a number of small things - get that hull & gear shining.
Then verify no vacuum leaks, good ignition timing. Might consider a fuel mixture check as well. Fuels have changed, you could be a jet size off or two. Small things add up! I was amazed when I last had my boat up on a lift at how much effort it took to get things really cleaned up. Thinqer33
 
Yea I agree about the bottom & that the bottom would effect the RPM'S of both engines the exact same because a vacuum leak in both engines, or timming or any thing to effect both engines the exact same is a lot slimmer than a dirty bottom I already rebuilt the carbs, cleaned the fuel tanks, compression test ok, fuel flow meters are running the exact same so first thing come spring after claw in the bottom is to WOT and see what KT'S I get. Thanks bob
 
what kind of numbers are you seeing on your fuel flow meters? I dont have any on my boat I wish I did. My boat has twin 75 gallon tanks. it may be cool to exchange some pictures of our boats.
 
1000 rpm. 2 gph
1500. Rpm. 3 gph
2000. Rpm. 6 gpm
2500. Rpm. 9 gph
3000. Rpm. 15 gph
3200. Rpm. 16 gph

thats all I got with my rpm problem may be the bottom of my boat was dirty but at any case you will either get the same, close, or better. And I have twin 318's with 4699s carter carbs & 1:5 to 1 paragon v drives hope this helps before I put the flow scan meter in I never new what was left in my tanks gas gauges are good but these are +/- 1%
 
Very ez 4 wires and a sensor in line with the fuel line there about 300 bucks, what I did was put a quick disconnect after both water seperators and I can switch which engine runs off whitch tank I choose so with one gauge I can switch back & forth for the most part at the same rpm both engines did use the same amount. And yes those readings are for 1 engine only. I will be buying the second gauge this year. There good because the record the total consumption and keep it till you reset so if you have two gauges you will know to 1% of what is in your tank. Plus I use them when planning a trip if I need to get there in a hurry that's one thing but if not run your engines at best fuel flow for longer consumption. Every boat I get at least one of these go in. And you can also tell if something is running wrong if your gauges do not match. You can also but a dual gauge but I prefer 2 gauges with separate total readings. But yes get at least one to start it will be one gauge on your dash you use the most besides your tack
Good luck bob
 
I have the same low rpm problem since rebuild. Could the mechanic have put the wrong gears in the transmission? Everything else on the list above checks out.
 
I will but as of now I rebuilt the carbs, new water seperators, plugs, set the timming, new cutless bearings, and packings, also cleaning the bottom. First time in the water this year I will run at WOT and post the results if she picks up in speed it was the bottom cleaning needed but I will post my results also my plans to rewire the entire boat but I don't think that had anything to hold her back to 3,200 rpm. Good luck with your boat and if you have Ny questions feel free to repost me. Thanks bob
 
circle hook said:
What is the best thing to use on all metal pieces under the boat I guess it must be bronze my props, rudders, & drive shafts that the only thing that got growth on it the fiberglass was clean
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I had great results with Trinidad zinc coating spray paint. Paint all underwater metal. I concentrate on the hubs of the props and leave the the outer half of the prop blades bare. They must see higher speeds through water and never get barnacles on the blade tips. I do this because I was told that painting the prop can slow the boat down. I had very little barnacles when I pulled it this year. I am in brackish water in the Chesapeake bay. My shafts use to look like corn cobs when I used bottom paint or bare metal. I only had a few with the zinc spray paint.
 
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