200 HP Mariner 1994

[Bob La Londe]

Anybody have any idea what the labor time should be to change out the power head on this motor?<br /><br /><br />I have a 1994 200HP FI Mariner on a 20' Baker tunnel hull. When I first got it the prop that was on it was way too short. It had a 23P high five. If I wound it up it would run over 7000RPM and run 70+ mph (pedo tube and speed wheel both). I never ran it that way, except for a minute when I first got it to see what it would do. It had 125lbs comp on all six cylinders per the invoice when I had it checked out before I bought it. I figured to reprop when I had a chance to take advantage of the output of the motor since I fish tournaments and speed running up river can make a difference.<br /><br />I do have some taller pitch props now, but I can't get the speed out of them. <br /><br />I got it hot once running the motor a little too high on the hydraulic jack when running a sandbar infested section of river. I immediately shut it down and wait for it to fully cool off before running it. <br /><br />It still has 125Lbs comp on all six. I have had the fuel rail removed and cleaned. Everything has been checked out, but it now only runs 55 (60 with a light load and a taller prop) mph and struggles to get to 5800 RPM with any prop including the original prop I had when I bought it. <br /><br />Any suggestions? <br /><br />Diagnostics I should check?<br /><br />It starts easy and runs smooth. <br /><br />The only thing that bothers me is the tach seems to cut out. My "mercury certified mechanic" claims it is probably a bad tach. He also claims the motor is running perfectly.

 

[Kenny Bush]

Re: 200 HP Mariner 1994

5800 is about where that baby should be at WOT.

 

[Bob La Londe]

Re: 200 HP Mariner 1994

I am aware that it should run 5800 RPM at WOT, but it should be running a heck of a lot faster. These are the kind of speeds a 150 gets on a similar weight boat.

 

[LubeDude]

Re: 200 HP Mariner 1994

Ok, After rereading the original post again, I see that you cant even get the RPMs out of the original prop now. You need to do a leakdown test, you might even want to pull the heads to take a good look at your cyliders. Something is holding you back that is for sure.

 

[Bob La Londe]

Re: 200 HP Mariner 1994

Originally posted by LubeDude:<br /> Ok, After rereading the original post again, I see that you cant even get the RPMs out of the original prop now. You need to do a leakdown test, you might even want to pull the heads to take a good look at your cyliders. Something is holding you back that is for sure.

Exactly how do you do a leak down test? I assume it is some form of pressurizing the cylinders and seeing how fast they leak down, but I am not sure how you would go about that.

 

[LubeDude]

Re: 200 HP Mariner 1994

You are correct in you assumption asto how it works. If you are not set up to do it, you will have to have it done at a reputable dealer. The cost of the kit may be as much as the price to have it done. Make sure they know what you are talking about, and actually have them show you the kit they are going to use. Some places will just tell you they will do a leakdown only to do a comp test. You can buy a kit through places like Summit or Jegs.

 

[Bob La Londe]

Re: 200 HP Mariner 1994

Thanks. I ordered a leak down tester last night. A quick google search gave me a rundown on how to do it, except a number of articles seem to indicate it only works on 4 cycle motors. I am guessing if the cyclinder is at TDC and I put some kind of block or clamp on the flywheel to hold it in place I should be good to go.

 

[Bob La Londe]

Re: 200 HP Mariner 1994

Anybody have any idea what the labor time should be to change out the power head o this motor?

 

[KCLOST]

Re: 200 HP Mariner 1994

Are you sure you have spark on all the cylinders?

 

[Barlow]

Re: 200 HP Mariner 1994

I'm no mechanic but, spark was the first thing I thought about..

 

[LubeDude]

Re: 200 HP Mariner 1994

^BUMP^

 

[rabidfish]

Re: 200 HP Mariner 1994

Mercury "flat rates" 9 hours. To do it well I am guessing 10 - 12.