Lack of speed??!!!

Bradwim · Jun 11, 2011

Hi I'm new to this forum. I just bought a 91 rinker 186 has a reman 4.3 with 15 hrs. The boat runs great no problems other then runs 4200rpm 31mph by gps. Ha a 14.5" 17p prop. When I got it it had a 14.5" 19p prop. I know this boat should run 45mph at around 4700rpm any help would be great thanks. O and it has the 1.84 gear ratio in the out unit like it calls for thanks.

dingdongs · Jun 11, 2011

Re: Lack of speed??!!!

when you give it full throttle ,how long in seconds until it gets onto the 'plane'.may have 'sodden' foam under the floorboards so your theoretically lugging an extra 1/2 ton of water around.could weigh the boat but revs seem low too.

Bradwim · Jun 11, 2011

Re: Lack of speed??!!!

I don't know exactly how long it takes to get on plane. But the boat seems to b responsive and doesn't seem to take an excessive amount of time to plane out. Thanks

HT32BSX115 · Jun 11, 2011

Re: Lack of speed??!!!

Bradwim said:
Hi I'm new to this forum. I just bought a 91 rinker 186 has a reman 4.3 with 15 hrs. The boat runs great no problems other then runs 4200rpm 31mph by gps. Ha a 14.5" 17p prop. When I got it it had a 14.5" 19p prop. I know this boat should run 45mph at around 4700rpm any help would be great thanks. O and it has the 1.84 gear ratio in the out unit like it calls for thanks.

Howdy,

Are you making small adjustments in drive-trim after getting up on a plane to find the "sweet-spot"?

If you cannot get to the correct WOT RPM, there are other reasons that could be causing it.

If you go up to the "Adults-only" thread, there should be a thread in there that will give you all the possible reasons that could cause low WOT RPM.

13. List of possible causes of low WOT (Wide Open Throttle) rpm.

Bradwim · Jun 11, 2011

Re: Lack of speed??!!!

Yes I am playing with the trim. Just doesn't seem like even if I hit 4700 rpm witch is 500 or 600 rpms more then I'm getting now would get me another 15mph?. Maybe I should get it weighed to see if it has sodden? Although it seems to float at the right height and gets up to plane ok. But I will check out the other threads thanks.

HT32BSX115 · Jun 11, 2011

Re: Lack of speed??!!!

If you haven't checked the accuracy of your tach, you might do that. If the tach is off (as they frequently are) It will throw off your search for the real problem.

Bradwim · Jun 12, 2011

Re: Lack of speed??!!!

Ya iv been thinking that. Il check it this week when I take the boat out thanks.

Bradwim · Jun 14, 2011

Re: Lack of speed??!!!

Well I checked my tach it is off 3 to 400 rpm at wot. So I guess I'm running 3800 to 4000 at wot not sure where to go from here the boat runs so good it's very nerve racking!

fuzzybob · Jun 14, 2011

Re: Lack of speed??!!!

Are you sure the throttle cable is letting the carb go to WO? Might unhook the cable and see if you can advance further by hand. Good luck

Bradwim · Jun 14, 2011

Re: Lack of speed??!!!

I have opened the throttle up and looked into the carb seems to open straight up and down? Thanks

Bradwim · Jun 14, 2011

Re: Lack of speed??!!!

Well with some searching if found oil was a quart and a half over full. Oil was coming into my carb from the vacume line going to my valve covers and clogging up the flame arester. Cleaned everything and let out some oil well see tomorrow if it helps fingers are crossed!! Could this have been the problem?

81 Checkmate · Jun 14, 2011

Re: Lack of speed??!!!

Quart and half overfull, What color was your oil?

Lack of speed??!!!

Cadet

Chief Petty Officer

Cadet

Supreme Mariner

Cadet

Supreme Mariner

Cadet

Cadet

Petty Officer 1st Class

Cadet

Cadet

Lieutenant