Cylinder head

[RRRKKK]

Is there a difference in cylinder heads on a 1990 60hp Johnson and a 70hp Johnson I will need to rebuid the powerhead and am thinking this might be a way to increase hp on the 60, also are Boyesen power reeds worth the expense? This motor is on a fishing boat.

 

[jegervais]

Re: Cylinder head

I quick review of the common parts that make the horsepower differences shows, same block, same exhaust tuner, same cylinder head, same intake and same reed blocks. Differences are carb assembly and different carb jets.<br /><br />I jave no opinion on the Boysen reeds performance gains - I have heard however, they require more frequent replacement than stock metal reeds, I don't know whether or not how much truth there is to that story.<br /><br />-John

 

[RRRKKK]

Re: Cylinder head

Thanks John, dealer said the carbs were different and he thought the exhaust was also.

 

[walleyehed]

Re: Cylinder head

If this boat is used for fishing in the aspect of trolling, you will get way more back by installing the BOYESEN reeds. It's the single best investment you can make for an engine that idles much. It improves startability, will actually allow you to lower your idle RPM 2-300, depending on model, and your mid-range response will also show gains. Top-end however, will be affected very little if any.<br /> The only time a BOYESEN will break is if you don't richen the idle circut as stated in the instructions. If a reed does break, there will be NO damage from ingestion as would be normal for ingesting a stainless steel reed.<br />If the engine is torn down, put'em in....you will never regret it.

 

[OBJ]

Re: Cylinder head

Again what Kennyb said. Be sure to follow the installation instructions for the Boyesen reeds. Getting the reed cages dead flat is a must. Take your time with them. I installed them in my 84' 50hp Johnny about 6 years ago and have had no problems with them. I also have them in my 86' 90hp Rude. Good investment.