Anyone know this? 175HP Sportjet

[ferrellb]

Looking at a 2000 Sugar Sand with a Mercury Sportjet 175hp. I asked for a compression test and got the results. Two cylinders were 95 and four were 100. I have seen where they should be within 10% of each other BUT are all the numbers at an acceptable level for this engine? I have seen other engines where the levels should be around 140. I am trying to ask if 100 is okay? Thanks from a newbie!

 

[ferrellb]

Re: Anyone know this? 175HP Sportjet

According to Sugar Sand (tried the same question on their "contact us" portion of their website) they say it is shot. They said:

"Your compression should be at 130lbs. A two stroke will not fire unless the compression is 105 or better."

Either I am too eager with this boat or this answer seems wrong. The boat runs (spoken with third party). I am test running it early next week (unless I am told from someone that it is a waste of time). Does anyone know what the compression should be on a 175hp Mercury Sportjet? Thanks!

 

[Trent]

Re: Anyone know this? 175HP Sportjet

You could decarb the cylinders and redo the compression test before you give up. Or buy it at a reduced price to cover engine replacement if the decarb does not work.

 

[gss036]

Re: Anyone know this? 175HP Sportjet

Obviously 95-100#'s is too low. Most jet type engines run harder than standard outboard by the nature of design of the pump.
Decarb might help but I doubt it as those engines aare run a high rpm constantly, so reason to carbon up.
Go talk with a Mercury dealer/mechanic to find out for yourself. Unless you can get about a $3500-4000 discount for a new powerhead, personally, I think you are wasting your money. You are the one who asked for an opinion.

 

[ferrellb]

Re: Anyone know this? 175HP Sportjet

I really appreciate the opinion! I called Mercury Customer Service and explained the question. They said the numbers are well within range?! They said to pull a plug, shed light through the hole and check for scoring.

Now I am completely confused. More opinions please....