dcobbett

engine hours

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How many is too much.

Bought a Yamaha V-4, 130 crate engine and I have about 1,300 hours on it now. Had problems with it this past season and ended up replacing the fuel pump and re-building the carbs. Runs much better now, but, obviously, not as good as new.

Question is, how many hours is too many hours, and is it time to start looking for another engine?

Boat is a 1976 SeaCraft 20 which are very sensative to transom weight.

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Have you ever decarbed it?  Seafoam or the like?  Carbon buildup on the rings, not allowing them to 'float' is, IMO, what tends to lead to bad things with two strokes.  Particularly with those kind of hours.  A lean condition is the other big no-no.

 

I got 26 or 2700 hours out of a pair of carbed 200 yams before a connecting rod said 'hello' on one.  Not sure, but I think ethanol was the ultimate culprit, affecting a seal and creating a lean condition.   Just a theory, but whatever.  Decarbed them every 50-100 hours.

Edited by makorider

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I am surprised many people don't use Ring Free with every tank fill up.  I've had 10 outboards over the years both 4 strokes and 2 strokes and never had issues with carbon build up or carb problems, Most ended their life from rust out issues on the 2 strokes.  No ability to flush the old ones when wet stored.at a dock. I also agree ethanol is a disaster for the older motors.

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My usual de-carb process is to add a can of SeaFoam to a gallon of fresh gas and run the engine at a fast idle for 15 minutes, shut it down for 15 minutes and repeat that cycle for 2 or 3 times or until the gas is gone, then get off the mooring and cruse around the harbor for 15 to 20 minutes and then blow out what might still be in engine by reattaching the motor to the main fuel tank.

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Compression numbers don't look too bad. Cylinder number followed by compression number: (1)155, (2)150, (3)150 and (4)145.

Now I can't figure out how Yamaha numbers its cylinders. Just what cylinder is No. 1?, etc., etc.? Any thoughts on that question?

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Bottom Cyclinder  is normal always the worst one.  That is typical.  When you did the compression was the engine ran before hand to operating temps . When you did compression was the throttle  wide open  for each cylinder  test? These two things help give a more accurate reading.  

 

You said you rebuilt the fuel system.. did you use standard zip ties or the yamaha grade zip ties for the carb lines.?

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I didn't do the compression test my self. Couldn't find or borrow a gauge so I took it to a place in Marblehead that works on Yamaha motors. I assume they did it properly, if you know what I mean. Re-built the fuel system; what I did was remove the carbs and took them home, cleaned them and overhauled them using Yamaha re-buid kits. I didn't use zip ties on the fuel hoses when I put the carbs back in. I used SS band clamps, the ones that have slots in the bands that open/close using a screw driver to turn a spiral thread that locks into slots in band to tighten it around the hose. PIA, small space, but I don't think those clamps will loosen up.

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I had a YMI  2003  150HPI   w/1200 hours & only had a computer chip  problem  .the 1st year ,nothing after that .

I foolishly  traded in [screwed ]  for a 2012  150 4 stroke ……..  1100 hours ..I blew a hole  from the exhaust  thru the lower unit

 2200 to fix but no warranty  because it was rot & they couldn,t be sure it wasn,t somewhere else /

   the dealer had a 2020 200hp in the shop ………. not one else even had inventory .………….. 

   the 4 stroke was quieter & troll better ….but the drop from the HPI  I dropped in top end big time …..My hull had gotten a lot heavier  over the 1st  9 years & the additional  8 years as of this summer  plus the extra weight of the new trolling motor plus 3 more 12 volts

   I opted for the  new 200  using my old gauges & controls / wiring   etc …………………….  this one should outlive me because my hours have dropped big time to  / my aging factor  & the not fishing alone [for the most part] factor .

   they both had frequent oil & lower unit  lub changes & filters &  should no work .

 

   once you go over the 200hp  its a whole new engine .I had a friend get a 250 the same time as I bought mine & had another that bought another boat that had a 2017   300 hp   on it ……..Holy **** ……… both quieter , balls to the walls ………..   one has the electronic controls … I didn,t even know it was in gear …………..………  

      yet I have a commercial  friend that has a 90hp on a old Dyer made skiff …………..…..  hes still running strong   with 5500 - + hours

 

     the salesmen  said the Mercury has come back strong  & suks   for the money  and standard warranty are had to beat .just not enough qualified mechanics ><.,

I,ll probably haul out next weekend ><.

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