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Author Topic:   15ft 60hp merc EFI 4stroke performance
15ftlover posted 04-09-2004 01:33 PM ET (US)   Profile for 15ftlover   Send Email to 15ftlover  
Just replaced my 186# 4 cylinder '91 40hp mercury running SS 10inch x 14inch slightly cupped prop-would get me about 32-33mph fully trimmed and alone. New motor is 60hp merc EFI @ 236# smallfoot running 10 x 19inch aluminum merc prop. GPS WOT is 35-36mph (2 adults and a 4yo with big grin) Tack showing around 5300-5400RPM. Comments: new motor is very quiet with a little bit of idle shake (around 600-700), no smell, more torque (can sit at 2600RPM and mush)Can sense more bow rise. It has started every time on the first crank-scary, I'm not used to that. Cruise around 24mph at 3400.
Moe posted 04-09-2004 09:10 PM ET (US)     Profile for Moe  Send Email to Moe     
You sure that's a 19" prop? 5300-5400 rpm through 1.83:1 gearing and a 19" prop, at 35-36 mph, is 32-33% slip.


Capt_Tidy posted 04-13-2004 06:42 PM ET (US)     Profile for Capt_Tidy  Send Email to Capt_Tidy     
I just looked at the same in Yamaha (which is about 80% same as merc or is it visa versa?) for the 15...

On the idle end, what rpm pushs the 15 foot at 5 knots (minimum wake)... we do a lot of harbor running. It's got to be better than the old 70... they hate 1,200 rpm.

LHG posted 04-13-2004 07:19 PM ET (US)     Profile for LHG    
I believe Yamaha buys the 60 4-stroke engine from Mercury, minus the EFI induction, and puts it in their own package. Compare the specs and you will see. Same for the 30 & 40, while the 50 is the old joint venture
engine where Merc made the block, crank and pistons, and Yamaha the heads/valve train. Mercury no longer offers this in favor of the newer 50/60 EFI's.

Except for brand loyalties, it seems strange that someone would pass on the Merc 30-60 EFI's in favor of the same engine in carburetor version. I don't think there is any price premium for the EFI.

Peter posted 04-13-2004 08:05 PM ET (US)     Profile for Peter  Send Email to Peter     
Must be the color. ;)
Moe posted 04-13-2004 08:49 PM ET (US)     Profile for Moe  Send Email to Moe     
I don't believe there's any way a carbed engine can run that speed anywhere nearly as smoothly and cleanly as the EFI. At that speed, a carb is most likely in the transition range between the idle/slow circuit and main circuit. Any gust of wind or other wake will drop its rpm below that necessary to pickup fuel from the main jet, yet the throttle will be open sufficiently that there will be less pull on the slow circuit, and the mixture will lean out. The EFI runs VERY smoothly regardless of the speed.

I'll also take the fuel mileage of the EFI any day.


15ftlover posted 04-15-2004 03:42 PM ET (US)     Profile for 15ftlover  Send Email to 15ftlover     
I need to appologize and correct my earlier post, my prop is in fact a 17inch (as pointed out by MOE) when I checked the stamp. The dealer had me thinking it was a 19inch. The EFI was a no brainer as my prior two-stroke was left sitting for about a year and the carbs fouled up. After a rebuild it never ran the same. I had taken meticulous care of the engine and used it year round until I left it at my parents house when I moved away (they said they'd be happy to take it out once in a while-which turned into never). The engine shakes a a little bit when idling at @ 650-700 rpm but is ultrasmooth in gear. The idling speed in gear is a little faster than I want (will need to drag a bucket to slow troll). I am still amazed and startled that it starts on the first turn of the key EVERYTIME

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