1989 Force 85 Hp No top end

[mrtool2u]

First off,I just bought this boat,so I have very little time into it.It is a 1989 Spectrum 19 ft aluminum,with a 1989 85 hp force.I know the boat has sat for a few years,possibly 2.It had a few misses at first this weekend,,which I believe was older gas,but once the newer gas was more prevalent,it was ok. OK,here is the deal,,,no trim,but the motor is in next to top hole.The motor starts and runs like a top,,,very quiet and smooth,,but I do not believe that is building max rpm's.The boat is running 30 mph with just me in the boat.The linkages are opening the carbs the whole way,,it just seems like it is not reaching max rpms.New plugs,,and new gas should be run thru.Like I said,,it runs great on top,,quiet,,but I believe too quiet.Any and all info appreciated.

 

[roscoe]

Re: 1989 Force 85 Hp No top end

If you don't have a tach, get one. While you are at it, install a water pressure guage. Recommended rpm for your engine is 4500-5500.<br /><br />I'm thinkin, gummed up carbs, and possibly low compression. <br />Do a decarb, then check compression. Take it for a ride. If no improvement, rebuild the carbs.<br /><br />Nice boat, but you'll want all the power that Force can give you. Take care of it.<br /><br />Search for "decarb process" in the past 7 days for details.

 

[The Marine Doctor]

Re: 1989 Force 85 Hp No top end

As Roscoe says... you are gonna need tach for us to be able to help you out.<br /><br />Its possible that the engine is getting 5500RPM...thats a big boat to have to move.<br /><br />TMD

 

[mrtool2u]

Re: 1989 Force 85 Hp No top end

I did a comp .check and I had 120 psi on all 3 cylinders,,,with the throttle closed,did not bother to bypass the safety switch.Like I said,,it runs like a top now,after about a hour of running.

 

[mrtool2u]

Re: 1989 Force 85 Hp No top end

OK,finally got the tach hooked up,,with just me in the boat,3900 rpms and 30 mph,with 3 other large dudes in the boat,26 to 27mph and 3750 rpm.I am doing the decarb tomorrow.The prop is a michigan wheel,part no. 071036,,can anyone give some info as to where find the pitch of this prop.Also cleaned and polished the bottom of the boat with no avail.I had 1 carb off and it was fairly clean.Honestly,could carbs drop the rpms by this much.Like I said before,the boat runs very smooth at top end,,,just has no top end,or rpms.Any and all info appreciated.

 

[tteal]

Re: 1989 Force 85 Hp No top end

mrtool4u,<br /> I too am having the same problem with my 19' Bayliner only reaching approx 3800k rpm (Teleflex tach) and reaching 28mph (gps) with 4 adults in the boat although I have a force 125 outboard. I've done a very thorough decarb and it did not help. I also changed the plugs.<br /><br /> If you find out what is causing your top end issue, I'd love to know so I can fix mine too.<br /><br />Take care,<br /> Tim