Hello,
I have posted another thread in the engines section about a previous problem i was having. It can be found here: http://checkmate-boats.com/forums/showthread.php?t=20228
Basically my 86 Diplomat with 140 hp Johnson was cutting out at higher RPMS and the tach was not working.
I since have put a new voltage regulator on and that fixed the inop tach, sort of. I don think its 100% accurate because at a hair above idle, the tach is readying 3000 rpm, however at idle, and higher speeds/rpms it seems like it could be pretty accurate. Its just that mid range that seems ify.
Any how... the main point of this thread is, who else has this same boat/ engine set up and what pitch prop are you running?
I ask this because even though i dont completely trust the tach, and the boat is still "cutting out" at high rpm, it is pushing just outside of the 5500rpm range (or so the tach says) when it cuts out. I called a local marina and asked if this type of engine has a rev limiter on it, they said they were not certain, but it might. That would explain it cutting out the way it does, however I currently have a 21 inch pitch propeller on the engine. and its cutting out above the 5500 mark on the tach (pushing 5800) all at around 40 MPH. I am thinking that with as light of boat that this is, maxed out on HP with that size of prop I should be going a lot faster. But then again if my tach is accurate, it means I needs a bigger pitch prop, which also has me concerned. I was speaking with a co worker today who sent me a table recommended propeller sizes and pitches for that specific engine (that again is a mid 80s 140hp johnson.) 23 inch pitch is not even listed in this table, and since I currently have a 21, it seems like I have reason to be concerned.
SO....if any of you have a mid 80s Diplomat with a 140 hp outboard motor, if you could tell me 1. what is your top speed, 2. engine rpm of that speed, and 3. what pitch propeller you are running I would greatly appreciate it.
Also, if you know if this engine I have has a rev limiter on it that would be great to because it would tell me if i still have an engine problem or not.
Thank you!
I have posted another thread in the engines section about a previous problem i was having. It can be found here: http://checkmate-boats.com/forums/showthread.php?t=20228
Basically my 86 Diplomat with 140 hp Johnson was cutting out at higher RPMS and the tach was not working.
I since have put a new voltage regulator on and that fixed the inop tach, sort of. I don think its 100% accurate because at a hair above idle, the tach is readying 3000 rpm, however at idle, and higher speeds/rpms it seems like it could be pretty accurate. Its just that mid range that seems ify.
Any how... the main point of this thread is, who else has this same boat/ engine set up and what pitch prop are you running?
I ask this because even though i dont completely trust the tach, and the boat is still "cutting out" at high rpm, it is pushing just outside of the 5500rpm range (or so the tach says) when it cuts out. I called a local marina and asked if this type of engine has a rev limiter on it, they said they were not certain, but it might. That would explain it cutting out the way it does, however I currently have a 21 inch pitch propeller on the engine. and its cutting out above the 5500 mark on the tach (pushing 5800) all at around 40 MPH. I am thinking that with as light of boat that this is, maxed out on HP with that size of prop I should be going a lot faster. But then again if my tach is accurate, it means I needs a bigger pitch prop, which also has me concerned. I was speaking with a co worker today who sent me a table recommended propeller sizes and pitches for that specific engine (that again is a mid 80s 140hp johnson.) 23 inch pitch is not even listed in this table, and since I currently have a 21, it seems like I have reason to be concerned.
SO....if any of you have a mid 80s Diplomat with a 140 hp outboard motor, if you could tell me 1. what is your top speed, 2. engine rpm of that speed, and 3. what pitch propeller you are running I would greatly appreciate it.
Also, if you know if this engine I have has a rev limiter on it that would be great to because it would tell me if i still have an engine problem or not.
Thank you!
