Hi everyone,
New to this forum and all I can say is WOW!!! Never learned so much in such little time about my Merc! I have a 488 and after reading understand some of its pitfalls and suggested upgrades like the 4" heat exchanger.
1st time boat owner and picked up an older boat for about $300 (owner was asking $1000). It has a 1984 488 (224 cu in/3.7l) with a 4bbl which had the engine rebuilt about 2 years ago, what exactly was "rebuilt" the previous owner did not know but the original 1979 470 is now a 488. I got this boat since everything is pretty straight forward, points, coil, carb, etc...
Anyway, when I got this boat the owner stated it failed him on the water and he would not figure out what was wrong. He got a newer boat so wanted to unload this money pit on me. So here I am... Fixed the spark issue (burnt points and dead coil), fixed the trickle of fuel issue at the carb, water separator and clogged mechanical fuel pump, so now have spark to the plugs and fuel to the carb. It turns over and "starts" when fuel is put directly into the throttle body but it was clear no fuel was going through the carb. I bought a Qjet rebuild kit for $25 but there are many issues with the carb after opening it up and it can't be rebuilt (mainly stripped threads where things were epoxied in place). At this point I am an additional $150 in (basic tuneup parts and fixing the issues above) so this boat has not hit the $1000 mark... yet
I looked here and see many of the 6/8 cyl motors have swapped successfully to a Edelbrock or Holley. On cars I have done the swap many times and it was pretty easy since I also swapped out the intake manifold and bought any aftermarket brackets to support the application. For this 4 banger I could not find any info on the swap. I will likely have to do some throttle linkage and fuel line changes but wanted to know if anyone has already done this and what it took. Any advice would be very helpful especially how the boat performed with the secondaries opened (lag?), linkage tips, fuel line routing, etc.
I believe the stock Qjet 4bbl is 750 CFM which seems like overkill for this engine. I am looking at a Edelbrock 1409 in a 600 CFM or a Holley 4150. The Holley 4BBL comes in a 570, 670, and 770 CFM with vacuum secondaries or a 600 CFM with manual (like the Qjet I have now). I have zero experience with the Merc 470/488 so do not know how much vacuum it will pull and if the vacuum secondaries will even open... or if I should think about a 2bbl (doh!). Since I got the boat DOA I have no idea how it ran with the stock 750 CFM Qjet. Any other carb recommendations?
Any insight and help would be highly appreciated. Thanks!
New to this forum and all I can say is WOW!!! Never learned so much in such little time about my Merc! I have a 488 and after reading understand some of its pitfalls and suggested upgrades like the 4" heat exchanger.
1st time boat owner and picked up an older boat for about $300 (owner was asking $1000). It has a 1984 488 (224 cu in/3.7l) with a 4bbl which had the engine rebuilt about 2 years ago, what exactly was "rebuilt" the previous owner did not know but the original 1979 470 is now a 488. I got this boat since everything is pretty straight forward, points, coil, carb, etc...
Anyway, when I got this boat the owner stated it failed him on the water and he would not figure out what was wrong. He got a newer boat so wanted to unload this money pit on me. So here I am... Fixed the spark issue (burnt points and dead coil), fixed the trickle of fuel issue at the carb, water separator and clogged mechanical fuel pump, so now have spark to the plugs and fuel to the carb. It turns over and "starts" when fuel is put directly into the throttle body but it was clear no fuel was going through the carb. I bought a Qjet rebuild kit for $25 but there are many issues with the carb after opening it up and it can't be rebuilt (mainly stripped threads where things were epoxied in place). At this point I am an additional $150 in (basic tuneup parts and fixing the issues above) so this boat has not hit the $1000 mark... yet
I looked here and see many of the 6/8 cyl motors have swapped successfully to a Edelbrock or Holley. On cars I have done the swap many times and it was pretty easy since I also swapped out the intake manifold and bought any aftermarket brackets to support the application. For this 4 banger I could not find any info on the swap. I will likely have to do some throttle linkage and fuel line changes but wanted to know if anyone has already done this and what it took. Any advice would be very helpful especially how the boat performed with the secondaries opened (lag?), linkage tips, fuel line routing, etc.
I believe the stock Qjet 4bbl is 750 CFM which seems like overkill for this engine. I am looking at a Edelbrock 1409 in a 600 CFM or a Holley 4150. The Holley 4BBL comes in a 570, 670, and 770 CFM with vacuum secondaries or a 600 CFM with manual (like the Qjet I have now). I have zero experience with the Merc 470/488 so do not know how much vacuum it will pull and if the vacuum secondaries will even open... or if I should think about a 2bbl (doh!). Since I got the boat DOA I have no idea how it ran with the stock 750 CFM Qjet. Any other carb recommendations?
Any insight and help would be highly appreciated. Thanks!