7.5 - 9.8 mercurys

[Waco]

posted yesterday about buying a new 20hp motor. but.....woke last night having what seems to be a brain fart,..or maybe not. I have a relative that has a 7.5 and 9.8 merc. Neither of them have been abused, they have sat in storage for most of their life. I believe them to be 1972-1973 models. I got both of them out last year just for the fun of it, and did a lot of work to them, got them both in running order (fuel pumps, carbs, oil, plugs, impellers, stators, wiring, etc..) anyway, my point here....I could probably by either of them for around 400-500 dollars. The only reason that I havent already looked into it is that while I had both engines on the water, at top end (maxin rpm's) they started to rattle quiet abit (sounded like it could be valves). I know the seal around the covers are deteriorated, so that may be some of it, but I was scared the **** things were gonna split, so I backed off and returned them in good working order. Should I be weary of these motors? Would it be a good idea to look into buying one of them?

 

[Trent]

Re: 7.5 - 9.8 mercurys

First they dont have valves..They are two stroke engines. Wondering if the rattle is the cowling vibration from the bad seal you talked about??<br /><br />400.00 for both would be more like it. They are not worth much. Worth more for parts.

 

[Waco]

Re: 7.5 - 9.8 mercurys

whats the chances of a two stroke engine flying apart like that? The seal is basically gone, so that is more than likely the rattling that I'm hearing. i dont know.

 

[Pursuit2150]

Re: 7.5 - 9.8 mercurys

Go with a NEW 20.You are taking a chance with 20 yr old engines,parts, maint. etc.

 

[Trent]

Re: 7.5 - 9.8 mercurys

On those size engines the chances are LOW.. However it does happen..I would not worry. Fix the seals and run them if you can get them cheap.

 

[dick]

Re: 7.5 - 9.8 mercurys

The rattle could be the rewind starter . Its common on those models, the engagment pawls wear and rattle about .

 

[12Footer]

Re: 7.5 - 9.8 mercurys

Like any used outboard, you take a chance. If they have good compression,run well, and haven't had that many hours on them, you could end up with a good deal. But ya never know.<br />I have a 7.5HP 1974 and it is rock-solid. It had these rubber stand-offs placed around the cowling rim. I had lost all bu one of them,and the thing would rattle as it reached harmonic throttle settings. I went to the nearby auto store, and bougt a can of "RIGHT STUFF" gasket maker.This comes in a "cheeze whiz" type can,and costs about 8bukz.. It is the same material GM and Mopar use for many gaskets,(ex; oil pan). Using a dab of this stuff in each original mounting point, I placed the cover back on,using a piece of saran wrap to keep the goo from sticking to the cover. 24 hours later, I removed the cover,removed the saran wrap, and put it back on.The lid is tight and quiet now.<br />Great stuff, that right stuff!!<br />What kinda hull do you want to push with this motor? Reason I axe is, my 12Footer aluminium antigue hull is nderpowered with the 7.5HP.