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Old 05-18-2017, 03:40 AM   #1
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Default 91 Maxum 1800XR Updates & Fuel Capacity inquiry

Greetngs once again. A few updates. I last requested some assistance with electrical stuff...wiring the factoy tach amd the factory kill swich to the non original 85 Johnson 70 O/B that came with the boat when I bought it. Compression test after first run 150, 155 & 150.
Here are some updates on the project:

A) Tach is wired and working correctly now
B) Kill switch is wired and working correctly

Add C) Speedometer is working correctly now (Compressed air & spray 9 thru the tube & a drill bit to the gauge, pick up was clear)
Add D) Removed "lawn mower style" fuel filter which was in line up in the splash well. Relocated the primer bulb from the fuel tank well to where the fuel filter was, installed a water separator fuel filter in the fuel tank well area.
Add E) While overhauling the fuel delivery system I found that somebody used 3/8 lines on the 3/16 nipples for the triple fuel supply lines to each carb and cranked the clamps on....I pulled them off with ease never loosening the clamps. Also found the lower hose of that trio to be slightly kinked as it was 3in too long so it got "stuffed" in there. I replaced the trio with proper length 3/16 lines.
Add F) The bottom carb had zero fuel when I removed each of the bowl drains but the crimped line was not the only reason. Whoever did the carbs didnt check the float setting and it was bent to the point that the needle never retracted to allow fuel in. I removed the carb, opened it up and found that...it was clean as a whistle in there but the float issue killed it from functioning. After confirming fuel flow from tank to motor I had to reset the idle adjustment. It seems they compensated for lack of fuel by increasing the idle setting! The result on sea trial one (prior to revamping the fuel delivery issue) was idle throttle only 3knots max! , go for throttle up and it bogged and stalled. Low run setting was fine but without fuel to carb 3, hi feed wasnt working. Sea trail afterwards....WOT @ 5300rpms, 25-28mph
Add G) Since this motor does not have power tilt/trim, I bought Smart Tabs SX 60lbs and installed them. With mid point settings and going to the 3rd hole with the trim pin the 5300rpms varied to 5000-5200rpms and speed increaed to 32mph, boat handeled better. planed faster and steering response inproved (even in reverse).
Add H) refueling issue. Ive refueled 3 times so far...once before the first outting (8 gals), once before the 2nd outting (6gal) and the 3rd time yesterday (5gals)
1st time, nozzle kept popping off, back splashing fuel and with the fuel gauge at less then 1/2 it took 8gallons and fuel was up to the neck.
2nd time, nozzle kept shutting off, back splash was less but still did it and it took 6 gals with the gauge at 1/2 to start.
WAIT>>>FIX THE ISSUE:
Problem one, fuel vent hose was 3ft longer then need be and looped high before connected to the vent on the starboard side. I cut that to lenght for a straighter run with a slight high lift a few inches before the vent outlet.
Problem two, the screen in the vent itself added restrictions. It wasnt caked with deposits but there was some restriction...about 30% Id say.
I REMOVED the screen. Couldnt think of a reason for it to have one.
For GP, I removed the fuel inlet tube at the tank end to inpect it. To be sure it was clear I used the excess vent hose (5/8 ID) to snake out the fill hose....it was clear and I reinstalled that. I also blew compressed air thru the vent hose from the tank side out. I blew low PSI air into the vent fitting on the tank as well. Reassembled everythin correctly.
3rd time refueling: Issue with noxxles and backwash is resloved. Still have to fill slowly due to pump pressure vs fill hose diameter but much much better. It took 5 gals this time with the gauge reading half way between 1/4 & 1/2. Kepp in mind, each tiome Ive fueld the rig was on level ground, my trailer sits the boat level when in tow.

And this brings me to my questiopn of the day. Fuel Capacity???
The tank tank is hard to read and the capacity part of the lable is unreadable. The tank model number is F020 something. According to parts list from manufacturers, that manufacturers tank modle indicates that its a 20 gallons tank. (resessed in the hull)
When we ran the boat for a few hours we got the gauge reading to 1/4. Then it takes 5-8 gallons to fill it...yet gauge reads about 3/4 or slightly higher. Visual inspection after fueling shows the fuel splashing at the top of the tank (plastic, I can see the fuel thru it) And I know these gauges "float" like old Chevys used to do) With this, its feel like Ive got a 10gal tank but I cant conceive that they'd put a 10gal tank in a boat thats rated for a 90HP motor.

SO...If anyone has a 91 Maxum 1800XR...chime in on the fuel capacity and the gauge reactions. I dont really want to attempt to take the sending unit out to replace it, nor do I want to try to "adjust" the float having to pull it out for that.

Other then that, I herby declare the Sea Chord ready to go!

Im sharing these updates in the event that others have similar issues and need any assistance. Fell free to message me if you do.

Ok so thats it for now.....Maxum'ers....let me know what fuel capacity youve got and how your guages react on boats from the early in the 90's!
Thank you...happy boating!
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Old 05-18-2017, 02:27 PM   #2
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Quote:
Originally Posted by SeaChord View Post
Add H)

refueling issue. I've refueled 3 times so far...1st time, nozzle kept popping off, back splashing fuel and with the fuel gauge at less then 1/2 it took 8gallons and fuel was up to the neck.
2nd time, nozzle kept shutting off, back splash was less but still did it and it took 6 gals with the gauge at 1/2 to start.

WAIT>>>FIX THE ISSUE:

Problem 1) Fuel vent hose was 3ft longer then need be and looped high before connected to the vent on the starboard side. I cut that to lenght for a straighter run with a slight high lift a few inches before the vent outlet.

Problem 2) The screen in the vent itself added restrictions. It wasnt caked with deposits but there was some restriction...about 30% Id say.
I REMOVED the screen. Couldnt think of a reason for it to have one.
For GP, I removed the fuel inlet tube at the tank end to inpect it. To be sure it was clear I used the excess vent hose (5/8 ID) to snake out the fill hose....it was clear and I reinstalled that. I also blew compressed air thru the vent hose from the tank side out. I blew low PSI air into the vent fitting on the tank as well. Reassembled everythin correctly.
Both the large loop and the vent screen are there for a reason.

The length of the vent line was to create the loop. The loop is run with the loop ABOVE the vent through hull so that water doesn't splash up the side of the hull, enter the vent line and run down into the tank. If it were looped BELOW the vent through-hull then it would create a trap. Either overflowing fuel or incoming water would gete caught in the trap and the vent would essentially be blocked. By looping above the vent, overflowing fuel will backflow back into the tank and any incoming water will backflow back out the vent overboard again.

The screen is there to prevent insects from crawling in and making a next blocking the vent. Believe it or not, this is very common. Mud daubers and wasps do it all the time.

The fuel backflow was from the vent not being able to vent air as fast as it was being displaced by the fuel being filled. The vent screen and/or corrosion inside of the vent is typically the cause.

Your solution should have been to replace the entire vent through hull and leave the vent line alone. I strongly suggest doing the following:

1) Re-install the vent line with the longer line and replace the loop ABOVE the through hull. Make sure it is properly secured.

2) Replace the entire vent with a new one. It will have a properly sized (uncorroded) aperture and a clear screen.
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Old 05-18-2017, 04:02 PM   #3
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I have enough line run and although I dont have a loop in it. I have a high point secured well above the vent tube to prevent the conditions you explained. I'll replacxe the vent itself in the near future. Thanks
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