Tweet
Howdy. New here to this forum. I'd like a little advice on a couple of issues.
1994 Ski Nautique Open Bow. 5.8 / 351 PCM EFI Pro Boss (TBI and not the GT-40) 1:1.23 PCM transmission. 625 hours. I've owned the boat for 5 years.
Issue One. When I'm running at idle for anything longer than 10 seconds or so, the engine seems to "load up" on heavy acceleration (skier pull-up acceleration). Very poor performance. Feels like a 4 banger vs. a V-8. However, if I go to neutral and give the throttle 3 or 4 "revs" up to 3,000 RPMs or so, and then immediately go into gear and accelerate, the performance seems to be normal. Also, the exhaust is a little more "gray" than I expect and I get a clear smell of un-burned hydrocarbons. Reminds me of the muscle car exhaust smell of the late 1960's.
Suggestions? I've heard that these early EFI units can be a bit troublesome and that parts are extremely tough to find.
Issue Two. I recently moved from the Houston, TX area to the Salt Lake City, UT area. In Texas, I ran an OJ Legend 3-blade 14X16 prop. W-O-T was about 4,600 RPMs. Boat really ran well (with the exception of the above-described issue). Fast forward to Utah and altitude. I'm typically running at 4,200 feet - with occasional trips up to 5,500 feet. I "propped down" when I came to altitude as I know that the engine performance is reduced by altitude. Texas prop was OJ Legend 3 blade 14 X 16. Just a bit "too tall" for this altitude. 4,300 W-O-T was all I can get. I decided to use an old OJ Legend 3 blade 14 X 14 that works OK, but my RPMs run about 500 to 600 too high at W-O-T. I bought an ACME 1868 4 blade 12.5 X 14.25 (based on a recommendation from ACME). Acceleration and hole-shot is good, but way too many RPMs for my liking. 600 to 700 too high. I'm looking at the ACME 422 or ACME 654. Anybody have experience with these slant-back SNOBS with the 5.8 running either prop at altitude? The Johnson site shows that the recommended prop for the 1:1.23 gearing is the OJ 428 prop 4-blade 13 X 15.5. Would y'all think that this would be similar to the original OJ 14 X 16?
Thanks,
JQ
1994 Ski Nautique Open Bow. 5.8 / 351 PCM EFI Pro Boss (TBI and not the GT-40) 1:1.23 PCM transmission. 625 hours. I've owned the boat for 5 years.
Issue One. When I'm running at idle for anything longer than 10 seconds or so, the engine seems to "load up" on heavy acceleration (skier pull-up acceleration). Very poor performance. Feels like a 4 banger vs. a V-8. However, if I go to neutral and give the throttle 3 or 4 "revs" up to 3,000 RPMs or so, and then immediately go into gear and accelerate, the performance seems to be normal. Also, the exhaust is a little more "gray" than I expect and I get a clear smell of un-burned hydrocarbons. Reminds me of the muscle car exhaust smell of the late 1960's.
Suggestions? I've heard that these early EFI units can be a bit troublesome and that parts are extremely tough to find.
Issue Two. I recently moved from the Houston, TX area to the Salt Lake City, UT area. In Texas, I ran an OJ Legend 3-blade 14X16 prop. W-O-T was about 4,600 RPMs. Boat really ran well (with the exception of the above-described issue). Fast forward to Utah and altitude. I'm typically running at 4,200 feet - with occasional trips up to 5,500 feet. I "propped down" when I came to altitude as I know that the engine performance is reduced by altitude. Texas prop was OJ Legend 3 blade 14 X 16. Just a bit "too tall" for this altitude. 4,300 W-O-T was all I can get. I decided to use an old OJ Legend 3 blade 14 X 14 that works OK, but my RPMs run about 500 to 600 too high at W-O-T. I bought an ACME 1868 4 blade 12.5 X 14.25 (based on a recommendation from ACME). Acceleration and hole-shot is good, but way too many RPMs for my liking. 600 to 700 too high. I'm looking at the ACME 422 or ACME 654. Anybody have experience with these slant-back SNOBS with the 5.8 running either prop at altitude? The Johnson site shows that the recommended prop for the 1:1.23 gearing is the OJ 428 prop 4-blade 13 X 15.5. Would y'all think that this would be similar to the original OJ 14 X 16?
Thanks,
JQ
Comment