Love this boat ..but still minor issues any thoughts?
- Thread starter Danosll
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- low end miss mid range
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Waterluvr
New Member
Only way to know is to block off and pressure and vacuum test the case if it's suspected. You can fashion block off plates from intake and exhaust gaskets used as templates, drill and thread a fitting on the intake plate to introduce vacuum. If it fails you can switch to pressure testing to find all the leaks, it's the only way to be sure.
Waterluvr
New Member
If you suspect a leak at the pto crank seal you can use a product that I otherwise completely shun for use in a 2 stoke motor but a quick spray of starting fluid at the seal while it's running at idle speed and already oiling will increase rpm's if it's leaking and is safe enough to use that way.
Just don't ever use that garbage to start a 2 stroke it can strip oil film off a cylinder wall fast enough to do some real damage before fresh oil reaches the piston(s) when it finally starts.
Just don't ever use that garbage to start a 2 stroke it can strip oil film off a cylinder wall fast enough to do some real damage before fresh oil reaches the piston(s) when it finally starts.
hotrodssnova
Member
Starting fluid works good to clean flooded spark plugs when you have them pulled out. I also use it in the same manner as you mentioned. Works great to find vacuum leaks on a "running" engine.
Waterluvr
New Member
The BN40-I Mikuni's and fuel pump on your boat in factory configuration are capable of supplying 100% of the volume of fuel at WOT the 787 is capable of using without getting anywhere near a lean condition so long as someone doesn't come along and undersize the factory jetting. In most cases a very small percentage of fuel increase on the H adjuster for the pto side will help that cylinder match the operating temperature of the mag side, but that's all you ever need to do for mods if your carbs, pump and fuel supply are all in good order.
If a high volume fuel pump somehow solves an issue, the problem is still there and you haven't found it in the fuel system yet.
Danosll
Active Member
Ok so i replaced fuel filter and disassembled carbs . Internal filters had some debris . So the filter wasn't doing its job .removed and cleaned jets, needles everything was good .wasnt able to perform pop off test..adjusted HS 1/8th ,low speed1 1/4.before it Would ru
n 6800 rpm 42 mph on gps. Changed rave valves and housings. Ran 7000-7200 rpm not sure speed. Amazing acceleration. Slowly tapered off to 6500 rpm 37 mph. Still is acceptable but once I got a taste of what it can really do . I wouldn't mind getting that back. Main jet 142.5 low jet 65.5 inlet 1.5 .. Took apart raves again all is good piston skirts smooth. Going to order new kits . I got some carb cleaner on one of the diaphragms . And I'm suspect I have an issue with my fuel pump
n 6800 rpm 42 mph on gps. Changed rave valves and housings. Ran 7000-7200 rpm not sure speed. Amazing acceleration. Slowly tapered off to 6500 rpm 37 mph. Still is acceptable but once I got a taste of what it can really do . I wouldn't mind getting that back. Main jet 142.5 low jet 65.5 inlet 1.5 .. Took apart raves again all is good piston skirts smooth. Going to order new kits . I got some carb cleaner on one of the diaphragms . And I'm suspect I have an issue with my fuel pump
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Waterluvr
New Member
They offer the best aftermarket kit available it comes complete with extra pop off springs and arms to, add two 1.5mm needle and seat's and a square accelerator pump diaphragm and your carbs will be good as new.
Waterluvr
New Member
Your low side adjuster needs to be set at 1 1/2 turns out, the high side on the mag seated and the pto high side I actually set on the water using temperature probes on both cylinders to get them running close it's more like 1/16 of a turn most of the time.
It's important to be thorough and service the entire fuel system and not just focus on the carbs, ethanol is very destructive to the linings of fuel hose and valve seals and all your gasoline contains a 5% or higher blend of it. That's why your seeing trash in the internal carb filters on the other side of the main fuel line filter. SBT sells a nice fuel selector valve and if your's is original it should be replaced. If the lines are original replace them as well along with a new filter and impulse line. Once you get the fuel system back in good order that boat is very dependable with outstanding performance in a single engine boat and you'll enjoy owing and using it a lot more.
It's important to be thorough and service the entire fuel system and not just focus on the carbs, ethanol is very destructive to the linings of fuel hose and valve seals and all your gasoline contains a 5% or higher blend of it. That's why your seeing trash in the internal carb filters on the other side of the main fuel line filter. SBT sells a nice fuel selector valve and if your's is original it should be replaced. If the lines are original replace them as well along with a new filter and impulse line. Once you get the fuel system back in good order that boat is very dependable with outstanding performance in a single engine boat and you'll enjoy owing and using it a lot more.
Danosll
Active Member
These were my plugs with adjusters in.
Danosll
Active Member
These are before I backed off adjusters
Danosll
Active Member
These are before I backed off adjusters
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