1994 Sea Rayder with merc 175 acceleration problems..

corstrat

Cadet
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Jul 4, 2011
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6
I bought this boat five years ago and only used four or five times each summer. Has worked fine in the past though at a top end by GPS of only around 42 mph seemed a bit slow on calm water. Since I have owned it, I have never had a real tune-up done. When I bought the boat, the prior owner had just recently completed the 175 conversion but other than that, I have no idea what he had done for upkeep.

This past summer after sitting for 10 months in the garage, I took it out. It started fine. But when I tried to accelerate, for the first few minutes it did fine taking me a mile from the slip all over clear deep water. Than it slowed down. Though going slow, the engine sounded normal at first as it slowed down making me think it was cavitation. Heading back to the slip I had to nurse the throttle to keep it running at maybe 5 mph. If I advanced the throttle too far it would stall and not immediately restart. After a minute stalled, I could get it to restart and it went back to the slow speed, but normal sounding engine mode.

My question is; does this sound simply like a cavitation problem, or motor maybe needing a tune-up or some other problem?

Also, would the 42 mph be normal for a 175 engine when running normal, or should I look into upgrading the impeller or other parts?

Any help would be appreciated.
 

Don S

Honorary Moderator Emeritus
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Aug 31, 2004
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62,321
Re: 1994 Sea Rayder with merc 175 acceleration problems..

Merc 175 what? Outboard? 2 stroke, 4 stroke? A Merc serial number would be VERY helpful.

what size boat? Can't imagine any PWC with a Merc 175 on it.
 

corstrat

Cadet
Joined
Jul 4, 2011
Messages
6
Re: 1994 Sea Rayder with merc 175 acceleration problems..

Sorry, I assumed when I said it was a Sea Rayder, it was understood it was a jet boat. And yes, adding the 175 Merc inboard to the jet pump is a fairly common conversion, But what I did forget to put up was it is a 1994 Sea Rayder.


Merc 175 what? Outboard? 2 stroke, 4 stroke? A Merc serial number would be VERY helpful.

what size boat? Can't imagine any PWC with a Merc 175 on it.
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: 1994 Sea Rayder with merc 175 acceleration problems..

You put the 94 in the title, so that wasn't an issue, and now you answered the other question, you have a 175 powerhead on the original 90 or 120 pump.

Are you sure the engine is in good shape? Compression test?
Is it firing on all cylinders?
You mentioned you hadn't tuned it up since you have owned it, how long is that 1 year, 10 years? Since it was new? Might be time for a full tuneup and compression check. Sure couldn't hurt.

Have you checked clearance around the pump and housing? It could be worn out costing you a loss of power out of the pump.
 
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