New here - Volvo 5.7 SX question

[DontStopBelievin]

Hello All,


Sorry for the long story, but here is my problem.

I have a 2000 Four Winns 248 Vista. The boat has a 250HP Volvo 5.7GS motor with a Volvo Penta SX (Single prop) outdrive. Boat is about 6500lbs. with full fuel and weekend gear.

Props tried: 15 1/12 x 15 3blade (Stock) and 14 3/4 x 15 4 blade.

My problem:

When I am on the boat alone, I am able to get the boat on plane and up to 4800 RPM. When I have anymore than two people on board, the boat is very sluggish to get on plane. This past weekend I had six average folks on board and I could barely turn 3800 RPM. Once I removed the people and went alone, I was back up to 4800RPM and on plane. Changing the prop doesn't appear to have made a difference.

I have tried everything I can think of including using the tabs and trim, moving people to the front to change the weight, changing to a 4 blade prop. I have verifed that I am below the weight the boat should be able to handle.

Any idea's on what to check? I feel like I've checked everything I can think of. I have one more thing I thought of today and that is the "Thrust washer". When I changed the prop I didn't see a washer on the aft end of the shaft. It's possible that I have been running all along without a thrust washer. The boat is 4 hours away and I'm unable to verify for a few days.

Would this cause my issue? Any thoughts on my problem?

 

[aky32433]

Re: New here - Volvo 5.7 SX question

Hi,
Has the performance degraded over time or has it always been like this? At 6500 lbs it seems like 250 hp might be a little underpowered to begin with. If thats the case, any other degradation in terms of performance would be really noticeable especially with extra people. I have a Stingray 195LR with a dry weight of 2600lbs and 225 HP (4.3 EFI Volvo). You can see the power to weight ratio difference with my boat. I routinely carry 5 people. As long as I have the weight distributed correctly, I get on plane fast and top end is not drastically affected. Since it seems like you have tried different props etc, and assuming your boat is carburated, I think your carb needs to be checked. Hopefully you have fresh high octane fuel and your filters are clean. Another assumption is that your engine is not "missing" which could indicate ignition issues. If it were my problem, I believe I would do a complete tuneup, plugs, wires etc, and probably rebuild the carburetor. While the plugs were out, I would also check engine compression. Whatever you do, it will probably be a process of elimination. I don't think the thrust washer is a contributing factor although you probably need to determine if it needs to be installed.

 

[hwsiii]

Re: New here - Volvo 5.7 SX question

Dont, we will try to help you as much as we can, but there is certain information that is needed in order to help you. The following form has all of the information that is needed to help you with your problems finding the right prop. If you do not know all of the information that is asked for on the form please give us the most information you have available, and especially all the information that is in RED as I have a program I designed to find the right prop for any planning hull boat that needs this information. It requires time to find all this information when we have to look for it and in my defense I expect you to be willing to expend as much effort in finding the right prop as I do. We hope to be able to help you get the exact prop you need for your particular uses, and this information is required to do that.


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