challenger 1800 wont restart in water

[Jdmak13]

Hey guys and ladies i'm new to the forum. I have a challenger 1800 with twin 787's. they both start right up when I put them in the water and i can run them for as long as I want with no glitches at any rpm. but if i shut them off and sit for awhile when i try to go restart them the one engine wont start, it cranks and cranks but wont start. So i brought it back to the launch on one engine and and pulled it out of the water and it fired right up after about a minute out of the water, so i put it back in and it started fine and ran but when i shut it off it still wont restart. I did this about 5 times with the same results. it sounds like water is leaking back into the exhaust or engine somehow when sitting in the water. is there a baffle in the exhaust that stops this? the other engine has zero problems and starts no matter what. is this a symptom of a bad RV?

Thanks, Josh

 

[Dr Honda]

It could be very high clearance int he RV... but I would be more inclined to think that the needle and seat is leaking in the carb. Basically... the engine floods, and since the exhaust is full of water... it's harder to get restarted.

This is a very common issue when an aftermarket rebuild kit is used.


With that said... the engine compression could be low. You should check that.

 

[Jdmak13]

Would it still run well if the compression was low? BEcause it runs really well right when I put it in the water. I did a compression test and every cylinder on both engines came out to exactly 60... I dont know if there was a problem with the gage or what. Im going to try a friends gage tomorrow.

 

[seadoosnipe]

I would def get a new gage and retest your motors. It's unlikely that you would get a bad reading of 60 psi on all 4 cylinders. Anything below a 100 psi signals rebuild. It's not just the numbers, it's the difference between them. A reading of more than 7 or 8 psi difference, means time for rebuild.

Get a new gage, do a retest. Oh, BTW,... a motor with low compression will start and run. But, when you try to torque it up, it won't create any horsepower to do work. It'll just die out on you.

 

[Jdmak13]

Thats the thing, it doesnt die out when I turn the throttle up. I had the boat loaded with 5 people and a cooler and it takes off at runs fine. Although after about a mile the one engine im having problems with now just shut off. It was hard to restart but i was lucky it fired back up and ran fine the rest of the way accross the lake. thats what baffles me is how well it runs with no hesitation at through the rpms. So ill check the compression today again with a new gage and post results. If not ill take the carbs off again and check the needle and seats. I was ready to tear it apart to get to the RV anyways, hopefully thats not the case.

 

[Jdmak13]

Ok so I took the carbs back off and i am going to clean them. I never got to get another compression test done. I then just removed the rotary valve cover and it looks brand new in there! So I then took the head cover off to inspect the top of the pistons and the cylider walls and their wasnt even one score mark nick in there, It was smooth and even all the way around. The one thing i did notice was i could wiggle the piston a little and the rings look a little lose, i dont know if this is where i would be losing my compression. I will post pictures tomorrow to see what you guys think. So i guess the only thing it could be what you guys said about the needles sticking and the engine flooding. Can I just clean them or do i need to get new ones and a new spring?

 

[Phildoo]

You need to verify the compression before anything.

 

[Jdmak13]

Pics of Pistons and bore

Here are some pics of the engine that was giving me problems... ill be getting that compression test tomorrow hopefully when i get the carbs back on. Let me know what you think!

 

[Cid6.7]

Sounds like faulty plugs like their misfiring once they start to warm up ?
Put everything back together do a compression test with new gauge & buy new plugs
See if that does it..

 

[Fat Cat]

Well on my 97' Challenger 1800 only 1 engine fired up for awhile, until I put the throttle down and eventually started it up. The 1 thing I don't like about SeaDoo is that they flood VERY easily, but it isn't impossible to restart.

 

[tballman]

Did you ever find out what the issue was? I am having the same issue with my 99' challenger 1800. One engine starts and runs great but the other has some unknow issue that has me stumped. It will start on the trailer, I back it in the water and it cranks strong but will not start for anything, pull it up the ramp and starts right up. Last time I went out I started it out of the water had someone back me in quickly and it ran great for hours, however when I shut it down to swim it wouldn't restart. I have had the carbs rebuilt (including OEM needle and seat), replaced the plugs, cut back the plug wires, replaced the gray fuel lines, chaged the fuel filter and replaced the battery with a new blue top. I have tried everything I can think of and everything I can find people recommending on here. All most forgot, compression checked out fine - nearly 150 in both cylinders.

I bought the boat last winter and have had it out three times this summer, each ending in a trip back the the ramp via tow rope. Its quickly becoming high dollar yard art. The guy I bought it off of said that it started and ran great, I quickly found out that he sold it in the winter so that no one would want to take it to the lake on a test ride. We just ran it on the hose and everything seemed to be great.

Does anyone know where i can get a shop manual for my boat? This site doesn't seem to have one posted.

 

[Jdmak13]

actually i went through the carbs again and replaced the needle and seats and just took it out about an hour ago and the problem seems to be fixed. I went out and ran it for about 45 min and took it back to the dock and shut her down for about 10 min and she fired right back up in the water so i took it back out and for anoter 20 min and beat on it a little then repeat and everything seems to be good. My compression ended up being 156/155. i wasnt surprised cuz the engine looks brand new inside when i took the head off and the rave cover off. I was beggining to think the worst of this boat, tball man sorry to hear ur problem but mine would actually start in the water the first time. Now all i have to do is wait till spring to fix some minor cavitation problems