my 85 hp runs but won't go full speed

i can run it with a fake-a-lake and it runs at high rpms, but out on the water it starts and runs but not at full speed. i wanted to know if the coils could be bad or is it a carbs/gas issue,any info/tips would be great on what i need to check or do.

NO load always runs great!! Try a compression/spark test. Then check the hoses for soft mushy.Any inline connectors can be bad and suck air. Check the fuel pumps diaphram.Clean the carbs.Check the tank vent line.Do that and post the results.

sorry for the interuption,but my 1987 50 hp force does the same thing.Just had two new ignition coils put in so I guess I will check the pump and gas lines and clean the carb.What do you mean by tank vent line jerry?Sorry i am a newbie and probably should have started my own topic but where i am having same prob thought i could use the advice given to you mulishaboat

Thank you Jerryjerry05 I'll try that and let you know the outcome. No prob Country69 im a newbie as well, the boat i have was giving to me and somewhat new to the 3 carb outboard world. I hope the info jerryjerry05 gave me can help you to.
i'll post results soon

Thank you Jerryjerry05 I'll try that and let you know the outcome. No prob Country69 im a newbie as well, the boat i have was giving to me and i'm somewhat new to the 3 carb outboard world. I hope the info jerryjerry05 gave me can help you to.
i'll post results soon

Yes always start your own thread. Some guys won't see your thread if you tack it on anothers?Add as much info as possible.Fill out the profile.Location? You might be close to someone who can help??Built in tanks have a line for escaping air so the tank doesn't swell and crack. If your running off a 6 gal carry on your vent is in the cap on older tanks. I understand they stopped putting in the vents on new tanks.Tey say just open the cap a bit to vent?????

Thank you for the info Jerryjerry05, i checked the compression and i have 130 in two and 140 in the bottom. I have two 6gal carry on tanks 1 new plastic and 1 older johnson, the new tank vent on cap was shut so i'll try that this weekend. thanks so much.

I would like to add that you don't want to run your engine at much more than idle while on the hose. The hose can't supply enough water even on full bore to keep the engine supplied with water.

You saying high RPM's on 'fake-a-lake'(which I assume are muffs with a hose) makes me cringe for your water impeller.

Good luck with getting the engine running! With those compression numbers, it's likely a spark or fuel problem. I would guess spark problem if it never has power in the water. Even if the tank was not venting, you should be able to get on plane right away after priming the bulb. If pumping the bulb up while trying to plane out doesn't help, it's probably an ignition issue.

Had same problem with Chrysler 75, which uses same Tillotson carbs, a few years back. Motor started and idled perfectly; wouldn't produce power. High speed jets were clogged. Unusual problem...usually it's the small idle bleeds that gunk up first, leading to hard starting and bad or no idle. Cleaned all three carbs and the Old Girl pulled 4700 RPM on the Nose!