1985 mercury 150 outboard

[golftrev77]

I have a 1985 mercury 150 outboard and having some problems. I took the boat out yesterday after working on it the past weeks and was having trouble getting it up to speed. the engine was idleing fine, however when we would start to get up to speed it would start to misfire and not go passed 4000rpms, yet when in neutral we could go passed 4000rpms. while in drive the throttle lever would be pinned to the max go yet were not able to go any faster than 30MPH. The engine would start to bog down and not run correctly. i felt as though it was trying to go faster but it would not get passed the 30mph mark. I recently had the carbs cleaned, new spark plugs, and flushed the fuel system. It is on a champion bass boat so there is no weight or overload issue. the idleing is fine it is only when it is getting up to higher speeds. Any ideas would help greatly because im stuck right now!

 

[sschefer]

Re: 1985 mercury 150 outboard

Before we start here lets understand that we don't know if the carbs were done right or not.

If we assume that they were then -

1. The high speed stator windings could be failing.
2. The fuel pump needs rebuilding.

It takes very little fuel and spark to rev to 4000 RPM in neutral but it takes a lot of fuel and spark to get to 4000 RPM in gear.

If the high speed side of the stator is failing it may have been your trouble all along and was miss diagnosed as a fuel problem. The same thing can be said for the fuel pump.

That last paragraph is exactly why j_martin, achris, myself and many others, preach the use of the good book by Merc... The Genuine Mercury Service Manual... it's gospel for sorting out your problems and getting you back on the water with the least amount of the green stuff missing from your wallet.

 

[golftrev77]

Re: 1985 mercury 150 outboard

Im assuming the carbs were rebuilt correctly... I am checking the other things you mentioned. Where could i find a copy of the mercury service manual? i have the one that came with the engine however its answer to most troubleshooting problems is to see an authorized merc dealer.

 

[sschefer]

Re: 1985 mercury 150 outboard

Im assuming the carbs were rebuilt correctly... I am checking the other things you mentioned. Where could i find a copy of the mercury service manual? i have the one that came with the engine however its answer to most troubleshooting problems is to see an authorized merc dealer.

Theres a sticky post at the top of this forum. I think it works for downloading the manuals.