compression

Hey everyone is 120 psi in each cylinder normal for this ski ? It’s a 2001 sea doo rx it seems to run just fine in the water hitting 59-60mph and rpms are at 7100 could my compression tester be bad ? Thanks for any advice !

Ski was hard starting in the water pulled it out and starts good on trailer for two seconds. Went back home tested compression and got mag side 150 and pto 125. Pulled engine and found some scoring on these. The gaskets seems flat and old. Are they shot? Should I go ahead and rebuild the lower...

Hello, I am new to the forum and to the Seadoo world. A buddy and I bought a 93 and 94 Xp this spring and his was running sluggish so I thought I would do a compression test. The 94 with the 657 engine is running at 125psi and is sluggish, can get up to speed but not very quickly. On the other...

Hello, I recently purchased a 1999 seadoo challenger 1800 with 787 engines in them. I’m having a few issues with them that I can’t figure out. 1- on one of the motors the compression readings are around 210 on each cylinder. And I’m not sure why that is. I’m no mechanic but that doesn’t seem...

Guys, I guess I need to sell this head because I cannot find domes anywhere.These domes are 36cc, and I want to run 95 octane so I guess I would need 41cc??.. Was going to sell for an ADA racing head, but your thoughts?

For sale, pictures show it is pretty clean. I havent even tried cleaning it so it should come out really nice.. The domes with it are 36cc, one dome has minor scars in it. Will ship USPS priority packed well. . Text 772-333-91three seven with your offer... I also have a Westcoast 44/46mm...

One of the engine head bolts on my 717 has sheared off. This is the second bolt in the last three years. Im currently reading compressions of 130 front end and 120 back end. Should i be concerned? Or when I fix this issue will this have an effect on my compression? The bolt and low compression...

Hi, I recently purchased a pair of GTX 155's less than 20 hrs. Before I put them in the water I run them & one of them I couldn't get it to crank. It was late at night & my wife got a bit confused with my instructions about when to turn the water on & I (she) may have flooded the engine, for...

Any help from you guys would be greatly appreciated .. Took boat out bout 20 times with no issues.. Last time out, on my way back in engine started smoking(white smoke).. Pulled cord.. Ever since it won't start up again.. It cranks and will start up for literally a second or 2 but that's it...

787 Lost compression on rear cyl. Can't see anything wrong with heads off. Pls Help Less than 1 week to the holiday weekend! ARGHHH! Engine cut out yesterday. Checked compression today - 60 psi on rear. 150 on front. Removed heads, cannot see anything wrong. Just gunked up head gaskets?

Hi Guys (and Gals), I am a newbie to the PWC world. I have boated for a few years but this fall I decided to pick up a project for the long Minnesota winter. I found an old 93 SP that had been sitting in some guys backyard for 5 years. Fortunately, he had a cover on it and his yard was...

After about 6 weeks of no use this last winter my Challenger 1800 w/ twin 787's wouldn't start the starboard motor...port motor is fine. Starboard engine cranks over normally, but doesn't start. Checked, found and changed bad fuel pump but still no start. Pulled carbs and checked fuel filters...

Looking for some advice to cheers me up!! I have rebuilt my engine from my GSX and couldn't get it to start. Turns out the compression is 50. No I didn't miss the 1 of 150. It is 50 and it drops to 0 on both cylinders. When I stop cranking. As I mention in a previous post I put the ski in...

I'm looking at buying a 99 gsx rfi with the 787 engine for $1700 with a decent double trailer (no rust, nice tires). I've got a 98 gsx limited and I wasn't sure how complicated the 787 rfi was compared to the carb'd 951. Is there anything bad about the rfi? It is a very clean seadoo with 109...

Hi Guys. I'm new to this forum as I just bought my first ski the other day. Does anybody know what the Compression Test readings should be for a 2008 RXP 155, or equivalent engine? My test from the shop reads: 1. 190 2. 180 3. 185 I've done a search and everybody recommends getting a test...

I was having starting problems with my 97 Gti. I haven't worked on 2 strokes much and was having a hard time figuring is out. Would run good the first run but after shutting it down, would always have a hard time getting it to start again. Would always eventually fire up and then run good but...

Instructions say to screw in to the same depth as plug, which is 19mm (3/4''). However, the only compression tester kits I see only specify 14mm thread. Am I to assume these will reach at least 19mm depth or should I get an adapter which specs list 19mm reach? I'm looking at this one since...

Need help on this one! Possibly even a therapist! 1997 XP 787 - Backfire / Flooding / Low Compression on 1 cylinder I just replaced a non-working coil with a pretty corroded one that had cleaned up to get a spark on this ski that was running perfect last year. Got ski to crank and sounded...

I have a 1995xp, the previous owner put on a high compression head(185psi) and after market flame arrestors. He could never get it to run and I ended up buying it as a basket case. I went through it and fixed his mistimed rotary valve, rejetted the carbs and replaced the leaking crank seals that...

According to the seller.... has less than 150 hour on it, it tops out at 55 mph. He's looking to get 5000 obo cash or a trade for a car or motorcycle about the same value it has the 2 stroke motor in it should the compression be between 150 psi, and 135 psi? Also what else should I be...