Progress! But still too hard to start on water - 96 Challenger

[mejim707]

After redoing the pop off again, and setting both MAG and PTO carbs to almost exact 35PSI I took the boat out this morning.

STARTING:
I ran it at the dock for about 30 minutes revving the engine and such then shut it down. waited 15 minutes and tried to start. It took about 3 - 4 minutes, on and off attempting at WOT to get it to fire and it did! That was actually great progress! But it's still not quite there yet. I don't feel comfortable shutting it down at a far away dock or even in the middle of the lake.

The engine starts instantly out of water and in water when cold. But after running a while then shutting off for 15 minutes it's more difficult to start in water but it does actually start now after a few minutes and some effort.

IDLE:
The idle is dead on 1400RPM in water. When sitting there in water the idle is not super smooth. It's not bad just not smooth. And low speed just putting along at 2500 RPM it seems as if the engine sputters a little. Not sure how it's supposed to be so maybe this is normal? I've never had a seadoo that was running tip top before so I have no point of reference.

ADJUSTMENTS:
I did adjust the butterflies to be in sync and low speed fuel should be dead on 1 full turn out and that's it. The oil cable / pump is also adjusted perfectly in line with the two reference marks.

PERFORMANCE:
When I hit the throttle it pops out of the hole with no issue, and runs epic at any cruising speed. At 75 - 80 % throttle I was doing a clean 40 - 45 MPH depending on waves so I know the engine is performing well. This thing feels awesome at speed, even for extended periods of time. I was running at 75% throttle for about 45 minutes straight with not a single issue flying at 40 - 45 MPH. I love it!

THOUGHTS?:
So, with all that said, what do you gurus think my next steps should be to diagnose this tough to start issue on water when warm?

As a last note, when the boat is sitting there, with the engine off, and I have the engine bay open, I can hear what sounds like water trickling in some place. There's no sign of water in the hull, no leaks at all, but I hear it! And it sounds like it's coming into the exhaust. Is water supposed to trickle into the exhaust when you're just sitting there?

Thank you all for all the help in the past and now! Much appreciated.

 

[DaddyLoafin]

Needle valve in carb leaking?

 

[mejim707]

Needle valve in carb leaking?

I did the pop off tests and both at at 35 PSI and held pressure after it popped and lost 5 or so PSI. But they held solid with no further drop in pressure. And after everything was reassembled I left the carbs with 15PSI for hours to make sure they held pressure and they did.

 

[mejim707]

Needle valve in carb leaking?

Actually, I didn’t start the boat when I got home. I washed it down and left it outside until a little while ago. I went to start it and it would not start at all. I pulled the plugs and they’re totally fouled. Covered in fuel.

I’m baffled, I did the pop off tests precisely by the book. And the needles and seats are brand-new 1.5 genuine Mikuni. And the pressure tester is a genuine Mikuni gauge. How on earth are the cylinders getting totally flooded with gas still? This makes no sense I’m freaking baffled.

 

[mejim707]

I pulled the air box. There’s fuel in the air box. I got the engine started but needed to hold it at WOT and it finally started. This is getting flooded and totally saturated / fouled from something.

One thing, I had the fuel turned off. It was 95 here earlier and the boat was outside in the sun with about 1/8-1/4 gas.

Could it be that pressure built up in the gas tank and when I opened the fuel lines the pressure pushed a bunch of fuel in?

I’m at a loss and really need help here. Other than pulling the carbs again and doing the same thing I’ve done a bunch of times already any additional advice on why I’m getting so much fuel would be greatly appreciated!

Thank you!!!

 

[DaddyLoafin]

Check the pressure relief valves for the tank

 

[mejim707]

Check the pressure relief valves for the tank

Thanks for the reply!

How do I check that? I can remove it but what would I do to check if it’s actually functional?

 

[mejim707]

Check the pressure relief valves for the tank

I pulled what I think is the pressure relief valve on the side of the boat. The air can move through this freely with no restrictions. I can blow through it and it doesn’t hold air back in either direction. I would think this should hold at least 3-5 PSI.

It’s just completely open air. Is this the incorrect part?

 

[brownie545]

If the 96 has a blower for the engine compartment I would suggest running that 30 seconds before starting warm. My 97 starts perfectly after running the blower.

 

[mejim707]

If the 96 has a blower for the engine compartment I would suggest running that 30 seconds before starting warm. My 97 starts perfectly after running the blower.

Does your boat have a fuel tank vent valve? It's called a "Vent Boat" part number "275500206" on the parts diagram. This would be in the side of the boat to vent the fuel tank.

If so, do you know if this is free flowing to the air? Of should it close so as not to allow water intrusion and to vent the tank when the pressure increases?

The vent on the side of my boat is totally free flowing to the air and will allow water to enter it no problem and allow water into the tank. This does not seem correct to me.

From what I understand the fuel system should be a closed loop system and should hold pressure. I don't see how that's possible if this vent it totally open to air and water intrusion.
I wonder if I'm getting water in my tank causing issues if this value allows water and air to pass through it freely..

Thoughts and insight from anyone on this would be awesome!

 

[mejim707]

Another 6:30am day at the lake. Had the boat out for 2.5 hours.

LAST NIGHTS WORK / CHECKS:
* Last night I backed out the high speed jets and reseated them to 0 turns and snug. I also reconfirmed the low speed jets were set to only 1 full turn out.

* I pulled the return fuel lines and reconnected them with metal hose clamps instead of tie-wraps for safely and to ensure there will be no possibility of leaks.

* I checked the "pressure relief valse" as I mentioned last night and that is nothing more than a screen to allow air to pass through with no restrictions. It's not a valve, it's just a tube with a screen so there's no possible way for gas pressure to build up in the sank of lines.

* Filled gas tank with 87 octane.

TODAYS OBSERVATIONS:
* The idle was smoother today. Not bad at all and idles right at 1400RPM.
* 1/4 - 1/3 throttle in the hole moving along the engine runs "ok" but kinda sputters. I'm not sure if it's backfiring at all but it's not smooth smooth.
* Zero hesitation hitting the throttle from a stop and pops right out of the hole on plane in a few seconds.
* I was hitting 40 - 45 MPH with no trouble with a full tank of gas and small waves today.
* Pulled the plugs after a 1 hour non-stop run at 75 - 80 % throttle. They were not wet this time. They were a perfect semi dark tan / cardboard color and dry. Exactly the way it should be. Yesterday they were black and very wet. Today they were semi dark brown and dry! Great improvement.

RESTARTING:
Went back to the dock and let it sit for 15 minutes after running if 75 - 80 % throttle for about 1 hour straight. It had trouble starting again and took about 5 minutes to get it going in the water. I had to keep the throttle fully open while turning it over.

IS THIS THE POSSIBLE ISSUE??
In order to get it to run, I had to remove the air box and the fire suppressor. I did not feel comfortable with that but that was the only way I got it to start.

Could the air box and/or the fire suppressor be impending air flow? From what I understand when you keep the throttle fully open when you're trying to start it, this increases air flow into the carbs. So removing the fire suppressor allowed air in with no restrictions and it fired up within seconds of removing it!

Any thoughts or help would be wonderful!

Final Note:
Sorry for all the comments, I'm trying to update as I get details, as I try thing and to be as informative as possible. I'm also trying to document this journey as well as possible in the event anything I'm experiencing and attempting would be helpful to others especially since this seems to be fairly common for these 787s.

 

[brownie545]

Exhaust leak? If it is sucking in exhaust it will not start well. I have also had to clean the fire arrestor before. Soaked it in degreaser.

I notice you didn't mention the blower. Mine starts significantly easier if I run the blower 30 seconds before starting as the manual says. If I don't use the blower I need half throttle and about 8-10 seconds of turning over. 30 seconds of the blower and it starts immediately with no tricks.

 

[mejim707]

Exhaust leak? If it is sucking in exhaust it will not start well. I have also had to clean the fire arrestor before. Soaked it in degreaser.

I notice you didn't mention the blower. Mine starts significantly easier if I run the blower 30 seconds before starting as the manual says. If I don't use the blower I need half throttle and about 8-10 seconds of turning over. 30 seconds of the blower and it starts immediately with no tricks.

Thanks for the reply!

I didn’t mention about the blower because whenever I try to start it I usually have the back opened so the engine is completely exposed. May be running the blower will pull more air into the compartment with the compartment completely open? I’m not sure but I’ll definitely try it. I’ll try anything at this point.

As far as exhaust, if the exhaust was leaking wouldn’t that also cause water to get into the heads? The spark plugs are completely dry now so I know the carbs are working properly and I would think if it was getting exhaust pull back it would also be getting water in the heads? What do you think?

 

[brownie545]

Thanks for the reply!

I didn’t mention about the blower because whenever I try to start it I usually have the back opened so the engine is completely exposed. May be running the blower will pull more air into the compartment with the compartment completely open? I’m not sure but I’ll definitely try it. I’ll try anything at this point.

As far as exhaust, if the exhaust was leaking wouldn’t that also cause water to get into the heads? The spark plugs are completely dry now so I know the carbs are working properly and I would think if it was getting exhaust pull back it would also be getting water in the heads? What do you think?

No exhaust at the head. Looks like you have a 787 from the pics. Generally leaks at the rubber connector between lower pipe and water box. Probably not the issue since its not starting well with the hatch open.

 

[POPPS]

Feel the exhaust hoses,,,see if they have collapsed,,,when the rubber coupler has a leak it’s always on the hidden side,,,excessive rotary valve clearance can cause your symptoms,..when it’s idling,,,look down the barrel of the carbs,,,is fuel dripping,,,

 

[mejim707]

Feel the exhaust hoses,,,see if they have collapsed,,,when the rubber coupler has a leak it’s always on the hidden side,,,excessive rotary valve clearance can cause your symptoms,..when it’s idling,,,look down the barrel of the carbs,,,is fuel dripping,,,

Thanks for the reply POPPS!

I'll check the hoses today! I don't see any signs of a collapse and I don't see excessive water in the bilge even after having it on the water for about 2.5 hours straight today. What will I notice? A weak feeling spot or a blatant collapse?

Also. I took pictures of the rotary valve (PTO SIDE) when I had the carbs off. I did not see any raised lip on the edge of it in the MAG opening but I do see wear lines on the face. I felt the lines and none seem deep as in my finger nail doesn't catch on any. They seem fairly smooth but I can tell they're not just a scuff, I can feel the unevenness.

Here's a few pictures of the rotary valve when I had the carbs off. Two different exposures to capture the as much detail as possible.

 

[POPPS]

If the hose has collapsed,, you will feel a separation of the hose,,,,how’s the compression,,,?,,,when it won,’t start what do the plugs look like?

 

[mejim707]

If the hose has collapsed,, you will feel a separation of the hose,,,,how’s the compression,,,?,,,when it won,’t start what do the plugs look like?

Thank you for the reply!

HOSES:
I'll check for a separation in the hoses shortly.

COMPRESSION:
The last time I checked compression, and I'll do so again today to be sure, the compression was 135PSI+ in both cylinders. I'll report back what it is today.

PLUG INSPECTION:
Yesterday when it wouldn't start the plugs were totally saturated in fuel and black! I re-calibrated the High / Low settings on the carbs and re-secured the fuel lines last night to rectify this.

Today when it wouldn't start the plugs were a perfect mid - dark brown and dry. No fuel and no fouling like yesterday. Not white either, they were the correct brown color and dry.

 

[mejim707]

If the hose has collapsed,, you will feel a separation of the hose,,,,how’s the compression,,,?,,,when it won,’t start what do the plugs look like?

I can’t find a separation in the hoses. I’ll keep checking.

Also, the compression is 132 PSI on both mag and pto. Not sure if that’s horrible or not.

I opened the throttle all the way and had both plugs out for the test.

I read people saying if it’s below 140 you need to rebuild the engine. Is 132 PSI the reason for this warm and difficult start issue in water?

 

[POPPS]

Doesn’t 135 psi seem low?..however…you have wet plugs on one occasion,,,and then dry on another occasion?

 

[mejim707]

I can’t find a separation in the hoses. I’ll keep checking.

Also, the compression is 132 PSI on both mag and pto. Not sure if that’s horrible or not.

I opened the throttle all the way and had both plugs out for the test.

I read people saying if it’s below 140 you need to rebuild the engine. Is 132 PSI the reason for this warm and difficult start issue in water?

Scratch that, tried a different gauge and it’s at 140 each cylinder.

The gauge fluctuates and it’s bumping north of 140 on each rotation but the needle valve isn’t closing fast enough to hold.

Not sure but it seems to be right at the 140 mark for both.

It was stupid hot today so the engine was hot even though it was just sitting. Maybe I should let it cool more and try again later.

 

[mejim707]

Doesn’t 135 psi seem low?..however…you have wet plugs on one occasion,,,and then dry on another occasion?

Sorry I replied before I saw your last comment, yeah yesterday I had very wet plugs before I readjusted the high and low jets on the carbs. I had the highs set to 0 but I think they were slightly out. After re-checking the highs and setting them to zero and snug, then the lows exactly at one turn out, today I had no fouling whatsoever. A medium to dark brown and dry. The plugs seemed perfect. The engine was warm to the touch even after ripping around the lake at about 40 miles an hour for an hour straight.

But I just tested the compression again with a different gauge and it’s approximately 140 psi but the needle bumps up a little over 140 PSI. Maybe that’s the reading I need. The engine is still warm from how hot it’s been here today. My tools were sitting in the boat in the case and I could barely touch them it was that hot.

I’m getting a third compression tester from advanced now. I’ll compare these two to see what the peak reading is when the needle bumps to its max. I’ve been using the mid reading when the needle bounces and maybe that’s not right.

 

[DarrenR]

Hey Mejim,
I think you split this into 2 different posts. Check out my reply to the first 1 if you get a chance.
I have a 97 challenger 1800 with similar restarting problems. I'm not near my boat and haven't had a chance to install but i am going to try going back to oem style fuel filter. I read something mentioning aftermarket or slightly clogged fuel filter not letting gas in. The fuel pumps on these are weak and might be insufficient for paper style filter.

 

[mejim707]

Hey Mejim,
I think you split this into 2 different posts. Check out my reply to the first 1 if you get a chance.
I have a 97 challenger 1800 with similar restarting problems. I'm not near my boat and haven't had a chance to install but i am going to try going back to oem style fuel filter. I read something mentioning aftermarket or slightly clogged fuel filter not letting gas in. The fuel pumps on these are weak and might be insufficient for paper style filter.

Sorry if I missed your message on a previous post!

That’s a good point about the fuel filter actually. The one I have now is a new genuine one. It’s not mounted up to the metal brace though. Perhaps that could cause a suctions or pressure issue. I’ll mount that to the respective bracket!

This is the one I have. Please ignore the way it’s tied up there lol

 

[mejim707]

I also rechecked my compression with the same compression tester I’ve seen other Seadoo owners use.

And I’m getting 140 solid on both MAG and PTO with 142-143 peak as the needle bops around. I am pretty confident my compression is good.

What I was doing wrong before was trying to get a compression reading with the throttle closed and one spark plug in.

Plus the way this thing responds on the lake it has no issue whatsoever getting to speed and getting up to 40-45 MPH with a full tank of gas.

I’ll test again tomorrow when I’m on the lake after running around a while that way I can test when the engine is at running temp as well.