95 150 Ocean runner mid range miss?

[ermess]

I have a 95 150 Ocean runner that starts and idles at 1200rpm out of the water. She has good hole shot, but when you get to about 3000 rpm she seems to have a miss (almost like a car diesaling) this goes on between 3000 rpm and about 4200 rpm. Once you get her above that she runs fine.
WOT is 5200-5400 depending on how I have her trimmed. When I bring her off WOT real fast she makes the same noises (diesaling?) not sure what the cause is. I would have thought if it was mechanical the noise would not go away at WOT.
Thanks
ED

 

[angus63]

Re: 95 150 Ocean runner mid range miss?

A pinging noise on rapid decceleration is normal for that v6. A noise at mid range rpm cruise is not. I would start with the basics. Compression test, spark test, wot timing check, sync and link, QL78YC plugs gapped at 0.03, fresh 87 octane fuel mixed 50:1. If these all are correct, then I would focus on the carbs for clogged mid-range jets.
Good luck

 

[ermess]

Re: 95 150 Ocean runner mid range miss?

Compression looked the same on all cylinders 110, good clean spark. timing is a little difficult since it is an optic eye. Is there any way to verify timing with out the special tool? I am double oiling - to verify VRO is working correctly- 50/1 in the tank + what ever is being used by VRO. Been thru carbs several times, replaced all float bowl gaskets, when I first opend them up, they were pickled in 2 stroke oil. Changed plugs. Would the double oiling cause the motor to be lean thru mid range?
Thanks
ED

 

[Dhadley]

Re: 95 150 Ocean runner mid range miss?

OK, you changed plugs. What plugs are you using?