Engine question

[nmhellraiser]

Like I stated in my previous thread, I'm a newbie to the boating world so don't bash me too hard. Here's my question, I have a 77 evinrude 115 that is giving me nothing but hell so I'm thinking of going with a 85 Merc. My boat is probably about 800lbs w/o passengers. I want to be able to pull a skier and go across the water about 30mph. Do you'll think the Merc is capable of this? Let me know what you'll think.

 

[kenmyfam]

Re: Engine question

Like I stated in my previous thread, I'm a newbie to the boating world so don't bash me too hard. Here's my question, I have a 77 evinrude 115 that is giving me nothing but hell so I'm thinking of going with a 85 Merc. My boat is probably about 800lbs w/o passengers. I want to be able to pull a skier and go across the water about 30mph. Do you'll think the Merc is capable of this? Let me know what you'll think.

Yes if it is set up and propped correctly. It will also depend on your hull shape etc.
What was it capable of with the 115 hp ????

 

[tashasdaddy]

Re: Engine question

you think you have trouble with the rude. wait till you start working on a merc. thats why i have all omc engines now.

 

[nmhellraiser]

Re: Engine question

Everytime I turn around it's something new. First was wiring then timing then carbs even went through a set of plugs before it was running. Now I'm down to the thermostat and impeller. I broke the t-stat housing last night so now have to get a new one. Is it possible to run w/o a t-stat? Don't see what it would hurt. Just have a cooler engine that takes longer to warm up. Anyways, like I said I think I've just invested in a new anchor.

 

[Silvertip]

Re: Engine question

Running without a thermostat is not a good idea. If it wasn't necessary, don't you think the manufacturers would have left them out? They are there to prevent "cold seizing" and to promote better idle quality. With your theory about a cool engine -- leaving out the poppet valve would help also -- not! If the engine you have runs well, fix the things that are wrong and run it. Sounds like the engine is basically sound. A service manual would help you understand your engine and make repairs much easier. Breaking a thermostat housing is not the fault of the engine. The man holding the wrench gets the blame for that.

 

[licketdsplit756]

Re: Engine question

thats what we get when the previous owner says he excellent care of it..says i dont really want to sell it. but i need the money? thats when the lights should come on.for the most part i run a 115hp 1985 johnson..pretty flawless really. i think if you take the time and patience it takes to do what your doing. youll find you have a good motor.as long as the compression is good. the rest is worth fixing up. consider the price of a newbee. at least now you know what you got.why start over.learning about the motor you have is a big part of owning a boat. theres alot more to it then gasup and go.. my wife does that with the car.

 

[nmhellraiser]

Re: Engine question

Looks like I'll be parting out this engine. Anyone need any parts off this? Everything minus powerhead and t-stat are good. Somehow within 2 days I've dropped compression in 2 cylinders. 2 have 120psi the other 2 50psi. I guess the Merc is going back on. Let me know what you'll think.

 

[ziemann]

Re: Engine question

Hold on-

Explain how you got to:

"Somehow within 2 days I've dropped compression in 2 cylinders. 2 have 120psi the other 2 50psi."

Does this mean you were finally able to run it and you burned it down?

Engines don't suddenly drop compression without a reason.

 

[nmhellraiser]

Re: Engine question

Hold on-

Explain how you got to:

"Somehow within 2 days I've dropped compression in 2 cylinders. 2 have 120psi the other 2 50psi."

Does this mean you were finally able to run it and you burned it down?

Engines don't suddenly drop compression without a reason.

I bought this boat about 1 week ago. When I got it, compression was between 110-120. I have not a clue how long it sat there before I got it. Parts and pieces were missing so I replaced them. I come to NM for the weekend to work on it and had it firing up everytime I cranked it over. Well the horn started honking and I shut it down and figured it wasn't pumping water so fixed that problem and put it back together and fired it back up and horn honked again. T-stat was the problem so fixed it and can't get it to start at all today. Check compression again and 1&4 are 40-50psi. 2&3 are still at 120psi. I'm not a boat mechanic but when I see something like that I assume that I need to dig in and replace the rings or look at other issues. All gaskets are ok and frankly I'm tired of messin with this motor. This will be the last OB I ever own. Next boat I get will be an inboard. I actually have a LS1 that is making about 475HP that needs a new home. Its time for a 408 in my TA.

To answer your question, I have seen engines drop compression w/in minutes at the track. I actually even mixed the gas a little fat to keep everything lubed up. Could be 100 things that went wrong. I was unable to keep it running until this weekend. For all I know, this motor could have been pulled from the bottom of the lake then sold to me. Alot could have happend once I actually was able to warm the engine up.