new to 1994 263 chase that was introduced with the transom extension. Single 250 Yamaha gets spray wicking all the way up to the engine cover. Cavitation plate sits even with the hull transom….not the added swim platform that Grady used to extend length for this model. water is hitting lower unit above the cavitation plate even with or slightly above the secondary spray flange on the lower unit. 30 inch lower unit standard on, but has anyone tried a short lower unit to alleviate this problem? I would think that there would be a lot of hydrodynamic eddying that would make a short shaft unfeasable. . The water wicks all the way above the engine cover and I’m worried that it will get into the lower unit.
1994 263 chase transom spray issue
- Thread starter Tuxedo4123
- Start date
Generally speaking, the anti-VENTILATION plate should be 1" above the keel for every 1' it is set back from it.
Are you sure that boat calls for a 30" lower? Most use a 25". Does Grady recommend a 30"? I'd ask them about that.
But, it sounds like you need to at least raise the engine - how much can you raise it? If not enough, then you could look into a new lower... or get a jack plate.
Are you sure that boat calls for a 30" lower? Most use a 25". Does Grady recommend a 30"? I'd ask them about that.
But, it sounds like you need to at least raise the engine - how much can you raise it? If not enough, then you could look into a new lower... or get a jack plate.
Ventilation plate….should have been more specific. Talked to Grady and they don’t really have info or specs on that old a model. The 30 inch is what is on the repowered engine that I bought the boat with. If I just raise the engine there would possibly be severe problems with very turbulent water flow as it jumps up from the hull to the raised platform then the platform actually RISES as it flows to the rear jetting the water upwards.
The original model did not need a jack plate..and I would assume Grady would not offer a model that had issues….wondering if anyone knows the original engine config.
Jack plate... I meant that as a way to use the existing engine and raise it up.
It's hard to imagine what you're saying about water "jumping" up without seeing the hull config. However, while on plane, water should simply be flowing off the lowest surface - wouldn't that be the main hull? All I can say is that with what you said in the first post, the engine is too low.
Can you better explain about your concern about "wicking" and "getting into the lower unit"? What does "wicking" mean? Are you saying you worried about water getting into the GEAR CASE and mixing with the gear oil? You do know that water is pretty much ALWAYS present inside the casing of the mid section where it meets the lower unit, right? The lower unit "case" is not, in any way, sealed to the mid case.
It's hard to imagine what you're saying about water "jumping" up without seeing the hull config. However, while on plane, water should simply be flowing off the lowest surface - wouldn't that be the main hull? All I can say is that with what you said in the first post, the engine is too low.
Can you better explain about your concern about "wicking" and "getting into the lower unit"? What does "wicking" mean? Are you saying you worried about water getting into the GEAR CASE and mixing with the gear oil? You do know that water is pretty much ALWAYS present inside the casing of the mid section where it meets the lower unit, right? The lower unit "case" is not, in any way, sealed to the mid case.
Good stuff… just started posting here, new to gradys, built my first boat with my dad in 1967.. built lots more since then, i will post some pictures here but the bottom line is I know the outboard is too low, Caroline at Grady customer service said she had never encountered this. Still wonder what the original transom to prop spec was…Grady didn’t have it.
Transducer isn’t the issue, this is massive spray 4 ft high in a fan config with water actually crawling up the engine to cover/drive housing interface…wish I could get you a pic but don’t have one…yet.
Blue tape shows water trajectory off swim platform. Problem is if I raise motor then there is substantial turbulence created from boat transom to end of swim platform due to substantial rise from end of keel to bottom of swim platform
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Good - thanks for those pictures - it makes it much easier to "see" what's going on 
So... while up on plane, even though you may getting some spray shooting up higher, the "main" water is still going to be coming straight off the bottom of the main part of the hull. At slower speeds, where you're really not fully up on plane... yes, I can see what you're talking about happening. But this should cease once you run faster.
From first glance, it looks like the motor is at the right height compared to the main part of the transom - just basing that on how high the anti-vent plate appears to be above the hull.
Honestly, I wouldn't worry about the water splashing up to the motor hood. It happens. But, you may be able to devise some type of deflector off the bottom, rear edge of the motor bracket. I'm thinking a very small "trim tab" type thing. Actually, a 2" piece of flat stock aluminum or SS (at whatever length you need) screwed directly onto the back side of the bracket such that it sticks down about 1" below the bottom edge should do it.
So... while up on plane, even though you may getting some spray shooting up higher, the "main" water is still going to be coming straight off the bottom of the main part of the hull. At slower speeds, where you're really not fully up on plane... yes, I can see what you're talking about happening. But this should cease once you run faster.
From first glance, it looks like the motor is at the right height compared to the main part of the transom - just basing that on how high the anti-vent plate appears to be above the hull.
Honestly, I wouldn't worry about the water splashing up to the motor hood. It happens. But, you may be able to devise some type of deflector off the bottom, rear edge of the motor bracket. I'm thinking a very small "trim tab" type thing. Actually, a 2" piece of flat stock aluminum or SS (at whatever length you need) screwed directly onto the back side of the bracket such that it sticks down about 1" below the bottom edge should do it.
Grady dealer in ColombiaSC and my outboard guru here in Lake Wylie SC recommended raising the moto 1 or two holes. Going to give that a try on the 21st. Thank you all for your input.
Yup - while it's hard to tell from the pictures, as we mentioned early on, you're "roughly" looking for 1" higher for every 1' setback. Put a straight edge on the bottom of the keel and adjust accordingly.
They appear to have gotten the extra length by using an extender(spacer) between the plates. You could probably go back to 25 by removing that, and replacing the driveshaft with a 25.
You need to talk to someone else at Grady, they definitely keep build sheets back to '94. Have your HIN for them to reference.
edit: In doing a quick Google search, that boat did come with single 30", or twin 25".
"The transom of the 263 Chase was designed for the ultimate in power flexibility. It offers the offshore angler the option of going with a single, 30-inch-shaft V-6 outboard (like Mercury's awesome 225 or Yamaha's 250 Saltwater Series) or twin V-6s up to 400 total horsepower. The transom is large enough to mount a 25-inch-shaft kicker right next to the big mill if you go solo, which eliminates the need for an add-on aluminum bracket."
You need to talk to someone else at Grady, they definitely keep build sheets back to '94. Have your HIN for them to reference.
edit: In doing a quick Google search, that boat did come with single 30", or twin 25".
"The transom of the 263 Chase was designed for the ultimate in power flexibility. It offers the offshore angler the option of going with a single, 30-inch-shaft V-6 outboard (like Mercury's awesome 225 or Yamaha's 250 Saltwater Series) or twin V-6s up to 400 total horsepower. The transom is large enough to mount a 25-inch-shaft kicker right next to the big mill if you go solo, which eliminates the need for an add-on aluminum bracket."
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I would have bet money that he needs a 25" lower but apparently not.
Hopefully raising it a hole solves the spray problem.