Hello I just purchased a 1998 Seadoo Sportster 1800. 170 hp. The boat had new Carbs installed but when I started the engines the left engine surged. RPM's shot up to 7500 then back to 2800 then stalled. this happened 3 times. I was able to restart, then accelerate up to 2800 Rpm's but if I gave it more throttle it again would bog down and die. When I would restart it sometimes I could run it up to 2800 RPM's for 10 minutes and then it would die again or if I try to throttle more than 2800 RPM's it would bog down and die again and again. Anyone know what is wrong? I don't know if this is electrical or a fuel problem? I checked the fuel filter and it looked fine?
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just bought a 1998 sportster 1800. new carbs installed. Surging engine
- Thread starter Rpd183
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mattbraafhart
Member
I would start by checking the throttle cable on the one that is having an issue to make sure it' connected and tight on both ends.
Throttle cable appears good. I spoke to the mechanic that last worked on this boat. He said this engine needs to be replaced. He said the other engine is great and was rebuilt. The engine in question according to him will run good for a while when adjusted before going out. This mechanic said it's working harder than the other engine and is the original 1998 engine. Does this make sense to anyone? Is this guy just trying to rip me off? If the engine needs to be replace then why did he put a brand new carburetor on it for the woman I had bought it from? This makes no sense to me?
mattbraafhart
Member
I'm just guessing but I'll bet that the one engine was not working at all and rebuilding one is half the price of rebuilding two, putting a new carb on the other was probably just an option she elected to do based on the list of things the mechanic probably told her to do. If it's a good mechanic he/she probably told her she needed to rebuild them both but she didn't want to spend the money and since it's working why bother.
Agree with Dr. Honda, check compression on all 4 cylinders and see what the differences are, then go from there.
My 1998 sportster is on original engines and carbs, compression is 135-140 on all 4 cylinders.
Agree with Dr. Honda, check compression on all 4 cylinders and see what the differences are, then go from there.
My 1998 sportster is on original engines and carbs, compression is 135-140 on all 4 cylinders.
Isaac-1
New Member
There are 3 or 4 issues that can come up on these Seadoo Rotax 717 engines that I know of that may mean a rebuild is needed in its near future, there are probably more than that, but I have owned my boat for less than a month now and am still learning about these engines. For me I ended up replacing one engine the week I bought my boat due to a rotary valve oil leak (leaking rotrary valve oil into the crankcase and fouling the spark plugs). So it can be things other than just compression that indicate a rebuild may be needed or at least suggested. Some of these things can be addressed short of a full rebuild, however a full rebuild may often be the smart move, as the cost difference between fixing the single issue and doing a full rebuild while you have it all apart may be minimal.
mattbraafhart
Member
Ask mechanic why he didn't rebuild other engine at the same time since he is recommending it now and why the other one was rebuilt in the first place, also how many hours since the rebuild of the other engine and the carb install, could just need new plugs. I had issue where plugs were fouled and caused similar issue to what you are having. This will all help you get a good baseline of the overall condition of both engines and what may or may not be needed in the future. All mechanically records and dates you can get your hands on and how many hours it's been run on average. This is just all good to know information that will help if you move on to another mechanic or start to take on some of this yourself.
Keep using the good oil (XPS), and NO-ethanol 87 octane fuel, winterize it properly, replace plugs every couple years and she will last a long time, these engines are tight if they are taken care of. I have two other PWC's with the same engines two years older still on original engines. Don't skimp on oil, never use anything but 87 octane NON-alcohol fuel, keep an eye on oil level and engine bay regularly to make sure things aren't leaking and it's using oil at the proper rate(manual says 50:1) Grease the drive shaft regularly every 3 tanks of fuel roughly. I still get 45 - 50 mph at 7000RPM but I normally cruise at 5000 -5500 RPM which equates to about 25-30mph depending on water conditions and burns about 10-12 gallons per hour at this cruise rate.
Keep using the good oil (XPS), and NO-ethanol 87 octane fuel, winterize it properly, replace plugs every couple years and she will last a long time, these engines are tight if they are taken care of. I have two other PWC's with the same engines two years older still on original engines. Don't skimp on oil, never use anything but 87 octane NON-alcohol fuel, keep an eye on oil level and engine bay regularly to make sure things aren't leaking and it's using oil at the proper rate(manual says 50:1) Grease the drive shaft regularly every 3 tanks of fuel roughly. I still get 45 - 50 mph at 7000RPM but I normally cruise at 5000 -5500 RPM which equates to about 25-30mph depending on water conditions and burns about 10-12 gallons per hour at this cruise rate.
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