Tohatsu 70 runs at 2/3's power

[Carolina Stevie Ray]

My 3cylinder Tohatsu 70 is running poorly - only gets to 2/3's power. I've removed and cleaned carbs and changed plugs. Fuel filter and pump are clean. These are 6 month old plugs, but were pretty fouled - it seems like there's a fine coating of oil all over the engine. Any advice before I start adjusting idle or throttle screws? Can I adjust the rate of oil flow from the oil pump?
Thank you for any help.

 

[TOHATSU GURU]

Re: Tohatsu 70 runs at 2/3's power

My best advice is to discover what is causing the problem before you adjust the oil flow...Instructions for adjusting the oil pump can be found in your owners manual.

 

[Carolina Stevie Ray]

Re: Tohatsu 70 runs at 2/3's power

Thanks Guru - any advice for what else causes fouled spark plugs? I assume that's the root of my problem.

 

[TOHATSU GURU]

Re: Tohatsu 70 runs at 2/3's power

Almost anything can cause a fouled plug. The best thing to do is start troubleshooting.

 

[kandil]

Re: Tohatsu 70 runs at 2/3's power

I would start with a comparison test for all the Cly

 

[Sea Rider]

Re: Tohatsu 70 runs at 2/3's power

If % of oil being delivered to engine is ok, maybe you idle or make very slow trolling like cruises for extended periods of time, plugs foul quickly, they are not reaching high temp as when at planing speeds or full throttle operation for some time.

When plugs are at high temp, the tip burns oil sticking on them, also avoids short circuited plugs do to oil, this does not happen when at slow speeds for extended periods of time. Before stopping engine after day's boating,full throttle for (1.5-2) minutes to burn oil from plug tips, will last longer. Other issue, maybe using incorrect spark plugs as factory recommended: NGK B8HS-10 or BR8HS-10 with 1.0 mm electrode gap.

Would also check head gasket torque is at correct torque and not loosing compression through head gasket.

Happy Boating