2000 14ft Challenger Twin 717's - Rebuilt?

[Roller25]

Hi Guys,

I'm trying to determine whether my boat has rebuilt engines in it or not. The entire engines and exhaust pipes are painted silver (it looks as though the engines were painted whilst assembled as the paint has been applied over the bolts as well). The boat actually runs well topping out WOT around 6000rpm (from memory), however the starboard engine seems to hard start after around 30 mins running. I've run a compression test with a cheap tool off eBay and all cylinders have come up with around 105-110psi, which seems odd taking into account its performance out on the water.

Anyhow, the reason I ask this question is because I am trying to determine whether a top end rebuild would be sufficient, but am wondering whether there is a tell-tale sign if the engine has been rebuilt without taking it apart? (Probably a stupid question).

Anyone know what colour these engines were standard around that time?

Cheers.

 

[Dr Honda]

What color is your exhaust pipe? If it's purple or cream... then the engine would have been cream colored.

I don't remember what year the changed the engine colors on the 720's. But I just serviced a 1999 boat, and it still had cream colored engines.


As far as your low compression... look in the end of the compression gauge hose. If there isn't a small check valve or a schrader valve... then it's going to read WAY low, because the volume of the hose will be added to the chamber volume. In the past year or two... there has been a flood of cheap gauges, that don't work properly.

 

[Roller25]

The pipe is also silver. It looks very much like the same paint that has been applied to the engines. The engines have definitely been painted as I can clearly see old chip marks in the paint layer underneath.

The compression test kit I have, although purchased off eBay, is identical to this one: http://www.harborfreight.com/compression-test-kit-66216.html#pr-header-back-to-top-link -and after reading some reviews, it appears they are junk, and often read as much as 30psi under. So maybe my problem is the gauge.

Thanks for your reply!

 

[Guest_User]

post some pics of the engines...

 

[Roller25]

 

[Guest_User]

well if I were to call it just by the pics and paint, I can`t say for sure if they have been rebuilt. The silver look more of a metallic paint than the solid colors used by an engine rebuilder like SBT. What are those marks in the corner of that head? if the paint over any sealant?

If I had to make a call, I`d say someone went hog wild with a spray can, and you won`t know until you actually take something apart...

remove the sparks plugs and look down in the bore with a flexible LED wand light and see if there are any numbers or markings on top of the pistons...

 

[Roller25]

I guess the paint is very slightly metallic - I think the camera flash is making it look more so though. I'll go take a look at those marks - kind of looks like someones hit it with a grinder from those pics.

I'll see if I can see anything down the spark plug holes, otherwise if I pull the head will I need a new gasket kit right away? Or are they rubber gaskets?

Thanks for the advice.

 

[Roller25]

I don't have a flexible LED wand light, but managed to get these pics of the top of the pistons.


The piston with the ashy build up is the MAG side and the dark heavy carbon build up is the PTO side. Could the appearance of these pistons give an explanation as to why I have a hard start after running for a bit (incorrect carb settings - lean?)

 

[Roller25]

Ok I managed to remove the head from the port side engine. After removing the head I noticed some water sitting in the jugs?? There also looks to be a fair bit of corrosion/white gunk stuff inside the jugs? The cylinder walls felt very smooth and I couldn't notice any grooves. The gaskets seem to be quite squished/deteriorated. Keeping in mind this is an engine that ran at 7k rpm with compression of 105 and 110 (using cheap compression gauge without Schrader valve - so I'm assuming it has possibly higher compression), any suggestions as to what I could I could do, or have done, by the looks of the pictures below to prevent certain catastrophe?

 

[Roller25]

 

[Guest_User]

rust is going to happen just from sitting. if it were very very rusty then I`d be more concerned. still hard to say if these were ever rebuilt. appears to be stock, wear on cylinders look like it has lots of use...
clear/sea water in the jugs could simply be from when you removed them, unless all was dry and you still found water in the jugs, then there is a possible issue...
Now there is a crap load of cleaning to do before assembly. chase the threads and clean the bolts, new gasket kit, etc etc...
From the pics, Piston wash appears normal for stock carb settings.

now it all depends on what you want out of the boat... if you have any doubt whatsoever, change the engines. if there is undetermined hours, throwing parts at it will not stop it from having a failure or issues down the road... IMHO if you are seriously keeping this boat for a few years, then go ahead and install remans, go thru the carbs and drive train and call it a day...

 

[Roller25]

I'm actually considering only keeping it for this summer (Australia), and then upgrading to a newer 4 stroke model for next season. So possibly only 10hrs use before I part with it. I know the pumps were only done just before I bought the boat, so they would have minimal hours on them.

What would be the best approach to cleaning the jugs/head up before reassembly?