GlastronCSS19
New member
Hey Everyone... here's my problem. First of all, Im an marine engineer (work on oil rigs offshore) and have decent understanding of marine gas engines, though Im far from a marine mechanic.... looking for a little guidance.
I have an 89 Glastron CSS 19 with a Merc 350 Mag in it. Just got through with a re-power.... Block up 350 mag, that is supposed to be 300HP. The boat before (old motor) was very quick, turned on hard and would do 63-64mph light load (re-power is because I learned a hard lesson about winterizing... wont happen again!). The guy that built this new motor told me it would be a noticeable difference with his new motor, and he fully expected I would be closer to 70mph top end. I put the boat in and took it easy for the first 3-4 hours running, though noticed even then it didnt feel right. Seemed very numb, even going easy during break in. Anyhow, The first time I opened it up (short burst of course) it only turned up to 3900 RPM's
and got the boat to 49MPH... it was an absolute slug. The motor idled fine and didnt miss fire, just didn't make any power at all!! I was on the phone with the builder immediately and he seemed very confused as to why it was happening as well. (The guy has supposedly been building marine motors for 25 years, and does have a good reputation)... Anyhow, after a few more time out and a few more phone calls to him I was pretty disgusted with the performance. With 4 people in the boat it wouldn't even come on plane!!! (Embarrassing)
I ended up advancing the timing a bit on the distrb cap, which helped. I didnt have a timing light, so Im not sure where it ended up. He tells me it was between 6-8 deg when it left his shop. I advanced up to where it started poping WOT, then retarded a bit. As of now, it's much better than it was but still seems to be lacking power from the last motor.
RPM's WOT - 4400 (should be turning higher, correct?)
59 MPH WOT
It puffs a little bit of smoke at start up, def smell oil burning, but nothing after that while its running.
Seems to be using way more fuel than it used to as well.
It does get out of the hole much quicker, starts good, idles smooth.... doesnt start hard when its warm, so I think the timing should be pretty close where its at??
Its the Rochester 4bbl carb, which wasn't touched during the swap, but ran very well on the other motor. The 4 bbl still hits and seems to be working fine. I did check the linkage and its opening up fully at WOT.
Still running the same SS 21 P 3 blade prop as it ran before as well.
The end of the day, its certainly better than it was when I first got it back, but I was definetly expecting more gusto than it has. Anyone have any ideas of what else I could check that might be holding it back?? Im not sure the cam that went into it... but I can find out if it would help.
He has told me to run it in some, that it may still be tight, though I have a hard time believing I will pick up 5 or 6 MPH from the engine wearing in??
He does back his work with a warranty and told me to bring it back to him if Im not happy... which is good, i just hate to do it as the season is getting short in my neck of the woods. Any ideas... comments... anything would be helpful. Thanks!!
I have an 89 Glastron CSS 19 with a Merc 350 Mag in it. Just got through with a re-power.... Block up 350 mag, that is supposed to be 300HP. The boat before (old motor) was very quick, turned on hard and would do 63-64mph light load (re-power is because I learned a hard lesson about winterizing... wont happen again!). The guy that built this new motor told me it would be a noticeable difference with his new motor, and he fully expected I would be closer to 70mph top end. I put the boat in and took it easy for the first 3-4 hours running, though noticed even then it didnt feel right. Seemed very numb, even going easy during break in. Anyhow, The first time I opened it up (short burst of course) it only turned up to 3900 RPM's
and got the boat to 49MPH... it was an absolute slug. The motor idled fine and didnt miss fire, just didn't make any power at all!! I was on the phone with the builder immediately and he seemed very confused as to why it was happening as well. (The guy has supposedly been building marine motors for 25 years, and does have a good reputation)... Anyhow, after a few more time out and a few more phone calls to him I was pretty disgusted with the performance. With 4 people in the boat it wouldn't even come on plane!!! (Embarrassing)I ended up advancing the timing a bit on the distrb cap, which helped. I didnt have a timing light, so Im not sure where it ended up. He tells me it was between 6-8 deg when it left his shop. I advanced up to where it started poping WOT, then retarded a bit. As of now, it's much better than it was but still seems to be lacking power from the last motor.
RPM's WOT - 4400 (should be turning higher, correct?)
59 MPH WOT
It puffs a little bit of smoke at start up, def smell oil burning, but nothing after that while its running.
Seems to be using way more fuel than it used to as well.
It does get out of the hole much quicker, starts good, idles smooth.... doesnt start hard when its warm, so I think the timing should be pretty close where its at??
Its the Rochester 4bbl carb, which wasn't touched during the swap, but ran very well on the other motor. The 4 bbl still hits and seems to be working fine. I did check the linkage and its opening up fully at WOT.
Still running the same SS 21 P 3 blade prop as it ran before as well.
The end of the day, its certainly better than it was when I first got it back, but I was definetly expecting more gusto than it has. Anyone have any ideas of what else I could check that might be holding it back?? Im not sure the cam that went into it... but I can find out if it would help.
He has told me to run it in some, that it may still be tight, though I have a hard time believing I will pick up 5 or 6 MPH from the engine wearing in??
He does back his work with a warranty and told me to bring it back to him if Im not happy... which is good, i just hate to do it as the season is getting short in my neck of the woods. Any ideas... comments... anything would be helpful. Thanks!!
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