88 SPL upgrade question

[TPD211]

Hi all,<br /><br />I was talking to a local marine shop owner who said he could put the carbs from a 115 HP Evinrude on my 88 SPL as a performance upgrade.<br />He was not sure of the HP gain but said it would be more than 10 HP.<br />He also said my current 5000 RPM would likely go to 5500 or so with no prop change.<br /><br />Any thoughts on this?<br /><br />Thanks.

 

[JB]

Re: 88 SPL upgrade question

Sounds like a very expensive way to get very little gain, TPD211.

 

[DJ]

Re: 88 SPL upgrade question

There's a lot more to it than that.

 

[TPD211]

Re: 88 SPL upgrade question

My cost is a 100 bucks for the carbs, installed.<br /> <br /><br />Will the carbs from the 115 give me any performance increase?

 

[DJ]

Re: 88 SPL upgrade question

Don't know. It may make it better or it may turn it into a pig.<br /><br />The 115 has more changes than that, such as a bubble back exhaust and port timing, I'm sure.

 

[TPD211]

Re: 88 SPL upgrade question

Ya, we talked about the exhaust and port timing.<br />The main thing is the larger carbs will push more fuel thru the engine = more hp, right?<br /><br />He said he has done this before and the performance gains are impressive for just bolting some carbs on this range of engines, the 88 thru the 115 hp evinrudes. <br /><br />The bore, stroke and cylinder size are all the same on this series of engines.

 

[DJ]

Re: 88 SPL upgrade question

You can let more fuel into it-true. However, it will do no good if the burnt fuel (exhaust) has nowhere to go.<br /><br />2-cycle engines are a balance of intake air/fuel and exhaust tuning.<br /><br />Playing with one and not the other, usually does not turn out too well.

 

[jerseyboy 41]

Re: 88 SPL upgrade question

Whenever you consider a performance mod take into account that there are never benefits without drawbacks. Is the meager h.p. gain worth losing the reliability and economy of what you have already? probably not. But think of it this way , its only a hundred bucks , put em on ,try em out and make sure the tech boxes up your old ones in case it does turn into a pig. You can always put the old ones back (they probably needed cleaning anyway) and sell the 115 carbs on ebay. If your anything like most of us youll probably spend the 100 on somthing for the boat anyway so go my son,modify and evaluate !!

 

[Dhadley]

Re: 88 SPL upgrade question

Most likely it wont happen. At 5000 rpm your holeshot probably is less than impressive now. Putting on larger carbs (venturi size) will not help that.<br /><br />Without changing the intake port size you can only flow so much fuel anyway. <br /><br />At 5000 rpm you are lugging the motor now. Change your set up to take advantage of what you have available but arent using.