Slow plane and slow speed

[jskinsey]

I have a 1975 Glastron V187 with a Chevy 250 inline 6. 165hp. I cannot get it to rev past 4000 unless the drive is disengaged. It runs a little rough at idle but when under a load even with only 2 people onboard it is hard to plane and when it does it doesnt go very fast(25mph). I dont know much about boats but I am very mechanically inclined. someone help me please my kids are going crazy to go out on the boat.<br />Thanks,<br />Scott

 

[jskinsey]

Re: Slow plane and slow speed

Oh yea..I have two props one is cast alum. 21 pitch and the other is a stainless 23 pitch...

 

[Don S]

Re: Slow plane and slow speed

Has it ever gotten higher rpm since you owned it?<br />Checking the high rpm in neutral is worthless information....no load on the engine, it should go 10,000+ then blow up with no load.<br /><br />

It runs a little rough at idle

That statement alone tells me it shouldn't get the proper rpm....... it's not running right!<br />Do a full tuneup, set the dwell (not just feeler gauge setting of the points), set the idle timing and check the amount of advance timing, also check the compression.<br />Then test it again and let us know if it idles smoother and runs better.<br />It takes all cylinders running properly to get the proper rpm.

 

[jskinsey]

Re: Slow plane and slow speed

Never been above 4000 give or take 100rpm. Will try the major tuneup today after work and let you know tomorrow....Thanks

 

[Bondo]

Re: Slow plane and slow speed

Don't Forget to change the Gas Filters...........