new 98 challenger 1800 owner with ?'s

Note: This site contains eBay affiliate links for which may be compensated
Not open for further replies.


New Member
Hello guys,

I have been looking over this site for a bit now to learn a little more before buying a jet boat. There is tons of great info on here!!!!! Awesome.
Now I just picked up a 98 challenger 1800 and took it to the marina to go over before I give up the rest of the money for this boat. The marina tested the spark and compression. Spark was great on all four cylinders but the compression was off. Starboard side 170/160 and port side 175/165. The dealer said beware that this was the beginning of trouble and that a rebuild is not far off on both motors. I am putting it in the water tomorrow for a test run. They said to try each motor and then both and see how they go.
Does this sound like a bad buy just based on the compression? It was winterized last winter and I haven't done a thing to it yet. What do i need to do if anything before putting it in the water.
I have read to dewinterize it and get the anti-freeze out, check oil, new gas etc... but the boat didn't have any water dripping after compression test. Did they even do that right or just not run the hose while having it running?
Guy's any help would be great! I want a jet boat but don't want to get screwed......
Matt Carr
Matt...think you need to kick the "mechanic" in the head.

You dont wanna run these boats, with 2-motors, 1 at a time, you'll flood the motor, thats not run'n and overwork the motor that is running. Those compression readings are somewhat high, but it could be do, to the winterizing, and the crap/liquid still bottled up inside the cylinders.

Go run the thing, with both motors, then see what happens. Should plane within 3-8 seconds, and hit mid 50's...:cheers:
I'm putting my steel toes on now!

Thank you for the response i wasn't sure to put this in trouble shooting or if would get more answers in general discussion. Anyway thank you Timmy, I thought the numbers were high from what I have read on here. Think the average was 140-150. Shouldn't there be some water dripping out also as I belive I read on here that before a compression test the boat should run for about 15 mins? Also with numbers that high should I run higher octane gas?
I am going to put in tomorrow and see how it goes and hopefully get back here with some good news and not that both blew and I was towed back to shore.

Again sorry if this seems trivial but I know nothing about these boats and am trying to consume as much info as I can.
Thanks again.
no worries Matt. Go run it, put regular gas in, believe the 787 should have 160psi, being "great", so think the extra psi, is the crap from winterizing. You can hook the hose up, fire the boat, then turn water on, for about 3-5 minutes. Then vise-versa, then dunk in water, and go rip around. Its ur gas goin in the tank, so BURN IT...wouldnt be bad, bring 4 new NGK-BR8ES plugs, capped at 22, and throw little bit of premix oil, into gas tank...wont hurt anything.
Good luck.
Just got boat back from 2nd dealer and they flushed everything ran it then did compression. It came back a little high but this time all cylinders were the same at 175. With it on the high side will it just run a little hotter or should I not even worry at all about it.

you by chance, notice any paint missing around the head-bolts. If not, then, probably the gauge is off. It happens and/or..remove the plugs, and with rag over holes, crank the motor, see if some/excessive oil shoots out.:cheers:
uh oh

i had to "limp in" on one engine last week for about a 1/4 mile at just over idle speed. do i have a ruined engine that is full of water sitting in my garage. i remember reading about blocking off the lines, but i thought that was over 15mph or so.

did you say the gap on the plugs should be 22 for the 98 challenger 1800? Just got new plugs and going to put the boat in the water tomorrow for its maiden voyage.
Not open for further replies.