compression lost quick

[caveman]

I have a 97 gti with a 2 1/2 year old engine in it. Ran great last two years. A couple week ago I took it out the engine would cut out and run hot. When cutting out I let off the throttle and it would idle back up just fine and run great for a while. If it did die it would always start back up no problem. I had seen the old grey fuel lines were still in it so I replaced all those and the carb was actually really clean when i took it apart. I put everything back together and turned it over and it did fire up for a second or two then died. I then put fuel mix in carb and tried firing it up again knowing it may take a few times to get pressure in the system to keep it running. Well aftor trying it for a while nothing. So I checked the compresion and it was 90 in both. My question is is ran great when i took it it out with full power until I ran it toppend for a while and it got hot. I would think it wouldn't have run well when i had it out with low compression. Does the compression get bad that fast? I will try another compression testor just to make sure my dads old one is not faulty. O
O yes. I does have spark

 

[kustomkarl]

Here is some information to review when doing a compression test;
Here is the correct info on a compression test. It covers all the basics.
To test compression, remove all the spark plugs. Place spark plug caps on the plug cap studs near the cylinder head to ground the empty caps. This completes the circuit of the ignition electrical system and prevents any electrical problems from the caps being un grounded. Using the correct adapter for the threaded end of the tester,( same length of the spark plug threads length)screw in the tester in one plug hole. Hold the throttle wide open. Push the start button. Watch the compression gauge, when it peaks out at the most compression, let go the start button. Read the psi number. I would do it 3 times to be sure it is accurate. Check both cylinders the same way. The ideal compression is 150 psi per cylinder. If it is less, it's not a problem as long as they are close to being the same. If the psi is less than 90 it might need be time for a tear down and a rebuild. If the psi in 1 cylinder is say 140 psi and the others are 80 psi you need to tear down and repair. This difference is a lot then there is a problem. I hope this helps you.
Let us know how you make out.

Karl

 

[caveman]

compression loss

We tested both cylinders about 6 time each and every time was 85 or so in each so the compression must have gone when we tried to fire it up for the first time aftor replacing the hoses and cleaning the carb because it had full power when we pulled it out of the water other then the few times it cut out. It looks as though a toppend rebuild this winter. SBT's kit is about $260 or so. Is that a good kit or should I look at another kit?

 

[kustomkarl]

That kit isn't too bad, and a lot of members us them. Try our "parts" link also for a parts source.

Karl

 

[caveman]

oil mix possible cause for overheat

Not knowing I shouldn't mix oils I have topped off my oil tank with about a quart and a half of Maxima marine pro oil. The shop was out of sea doo oil and said the maxima will work so I got that and put it in. A guy at another sea doo shop said that the oil mix should not cause overheating butt I just wanted some more opinions about it. Pleas let me know what u think

 

[kustomkarl]

This is what is recommended from seadoo as far as oil and fuel is concerned.
Use High quality low ASH API TC Injector oil.
Do Not use NMMA TC-W, TC-W2 or TC-W3 outboard motor oils or other ash less type 2 cycle oil. Avoid mixing different brands of API TC oil as resulting chemical reaction will cause severe engine damage. Never mix Mineral or synthetics oil together.

Never use fuel containing more than 10 % alcohol,( Methanol or Ethanol) as severe damage will occur. The minimum of 87 octane is recommended for most engines.

Karl

 

[caveman]

sea do oil mix

So can the quart and a half of the maxima oil make me run so hot and ruin the top end. If so then I will be paying a visit to the guys at the shop that sold me the oil. They more then likely wont do anything about it but I will give them a peace of my mind and they will know its not a good idea to put the maxima marine pro oil in a sea doo.

 

[kustomkarl]

You might want to look at the specs to see if it's what's recommended by seadoo first...It might be ok.

Karl