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I just recently finished rebuilding my 1995 150 60 degree intruder. I t runs great. I can run 50 mph on my 19 foot boat. The max rpm is 5000. All six plates in the carbs are open and the prop is only a 17 inch pitch prop. I am also runnning it on a jackplate. Why can't I turn 5800 rpm 's like my other OMC engines.
Did you check the timing. Sometimes after a rebuild it is neccessary to adjust the timeing and to adjust the linkage so every thing is lined up.
Something is off, 5000 rpms with a 17 pitch prop isn't going to be close to 50 mph.
MY handheld gps and speedo do not lie.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sapnfish »</TD></TR><TR><TD CLASS="quote">MY handheld gps and speedo do not lie.</TD></TR></TABLE>
Maybe so but, it might be that it's your tach is lying to you.
5000 rpm's, 17" pitch prop = a theoretical speed 44 mph @ 5000 rpm's with 0% prop slip.
If you were running 50 mph with a 17" prop @ 5000 rpm's, you would have -14% prop slip.
I would like to have one of those props.
What kind is it and where can I buy one?
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The tach is good because last week I pulled my 86 110 johnson off my boat that I built 6 years ago and ran it on the river. I ran wide open at 6 in the morning doing 45 mph and the tach read 5800 rpm like it always has running another 17 inch pitch prop but smaller diamter than the 150. I pulled the 110 off the transom and mounted the 150. Took it out for a test ride after 2 hours trolling around and could no go past 5000 rpm. Engine runs great, just that one issue. I am using the same controls and tach that worked fine earlier that day.
The prop that I am running with the 150 is a 15 x17 s.s. steel Michigan prop that I bought on ebay last year.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sapnfish »</TD></TR><TR><TD CLASS="quote">The tach is good because last week I pulled my 86 110 johnson off my boat that I built 6 years ago and ran it on the river. I ran wide open at 6 in the morning doing 45 mph and the tach read 5800 rpm like it always has running another 17 inch pitch prop but smaller diamter than the 150. I pulled the 110 off the transom and mounted the 150. Took it out for a test ride after 2 hours trolling around and could no go past 5000 rpm. Engine runs great, just that one issue. I am using the same controls and tach that worked fine earlier that day. </TD></TR></TABLE>
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Did you change the tach setting to six cylinder?
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No. I do not know if if says 6 cylinder on the tach. It is a faria tach and it says pulses. I will check this week. Thanks, that is a great idea. I never thought about looking at the back of the tach. I will keep you posted. Thanks again for your help.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sapnfish »</TD></TR><TR><TD CLASS="quote">No. I do not know if if says 6 cylinder on the tach. It is a faria tach and it says pulses. I will check this week. Thanks, that is a great idea. I never thought about looking at the back of the tach. I will keep you posted. Thanks again for your help.</TD></TR></TABLE>
Try this;
http://faria-instruments.com/s...t.pdf
Hope it will help solve your problem.
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