MERC 115 ELPTO !HELP!

[silverking]

Hello!,<br />I have a big problem: When Im at more than 25mph the motor tends to pull really hard to the right side. More speed=Harder pull to the right. At +50mph is almost a suicide!<br />I already try to correct it moving the fin a little, but nothing happens. <br />Also,wich one is the best transmission oil on the market?.<br />Any advice would be appreciated

 

[sho305]

Re: MERC 115 ELPTO !HELP!

You sure you have no damage down there? My old 150 inline6 has the fin only slightly offset to the right when viewing from the back and goes true until I get lots of trim, then pulls left big time. The big rooster is worth it though. I have run a stock 21, but have a Laser II 20 SS that lets it trim lots. Had to get $8 backset trim fin to fit this newer prop.<br /><br />On a 17 Checkmate it will run 50-55mph on a new speedo that reads close to or lower than others at 5500rpm or so. It is a '73 and I think more like a 115hp.<br /><br />Check your mounting to see if the motor is straight and all, and look for damage on the lower unit or bottom of hull. And if you have a fin mounted on the cav plate, make sure it is out of the water on plane.<br /><br />I think all the major names have good oil as long as it is specific marine lube to control water damage. The thickness of the oil seems to make lots of drag, so I think the synthetic oil is a bit faster and I can afford $3 more once a season. Synthetic is normally thinner than standard oil a bit, I think that is the difference. I used auto diff lube once for a short time in an I/O that was 90 and not 80 weight as the norm; and it slowed the boat considerably. Also found that it went faster with water in the oil, as it thinned it I am sure. I think I could use synthetic, and add about 10% of something thinner like 40 weight auto oil to thin it a little more for a good race mix. Have not done it though as it would only amount to a mph or less likely, and I can get more than that by sharpening my prop good. Racers run 10 weight mineral oil in manual trannys for an edge in cars regularly. I would rather see my expensive LU live longer. A friend of mine runs 500+ hp big-block Mercs, and changes his drive lube every month, in fact swears by it. His $9,000 drives hold up very well to the abuse on steady fresh merc lube only. None of my drives push the limits like that, so I run the whole summer if they have no water in them. Then again, I only burn 10-15 gallons of gas on the weekend, and rarely leave the boat in the water otherwise.

 

[silverking]

Re: MERC 115 ELPTO !HELP!

Thanks Sho..<br />How to check if theres some damage on the motor? everything seems to be Ok, no loosen or broken pieces, even the paint is intact. <br />The motor is a 96´ and the boat is a V-hull.<br />I,m affraid to let my wife take the boat cause some times it turns really hard, even to me.<br />Measured top speed is 55-60mph.<br />Thanks.

 

[RICKRICK1]

Re: MERC 115 ELPTO !HELP!

Not sure if this has been addressed;<br />1. Is the motor centered exactly on the transom.<br /><br />2. If centered and steering at neutral Centered is motor actually straight and aligned with v on hull.<br /><br />3. What tpye and is there slack in the steering system. <br /><br />4. Do you have a fin on the the motor, does it have torgue adjusters available. (Stingray)<br /><br />5. have you checked the underside of the boat, there may be a defect in the bottom v that is causing this (v not straight).